The Secret War: Spies, Codes and Guerrillas 1939–1945

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s) Would you make peace tomorrow?

The behaviour of most PoWs was strongly influenced by their own nation’s immediate circumstances. At this time, when Allied fortunes were plumbing the depths, a report on the handful of German PoWs in British hands recorded gloomily: ‘The officers (and most of the men) were quite immune to propaganda, think Hitler is a god and refuse to believe a single word of the British news.’ By contrast, a South African RAF pilot named Sgt Edward Wunsch provided his German captors with a highly sympathetic view of the Nazi cause, as recorded by his interrogator: ‘Like all South Africans who have entered Dulag Luft, Wunsch is an unashamed anti-Semite … [He says] There is no hatred towards Germany in South Africa, no enthusiasm for the war at all. Most people believe the nonsense press and propaganda tell them about German atrocities but … W. thinks it possible that one day South Africa could agree to a separate peace, if Germany continues to be militarily successful [author’s italics].’

The Allies lost the 1940 battle for France for many reasons. It has been a source of fierce controversy ever since, whether the French army’s defeat resulted from a failure of judgement by Maurice Gamelin, Allied commander-in-chief, or instead from a national moral collapse. It is unlikely that any amount of intelligence or advance warning could have changed 1940 outcomes. The German army showed itself an incomparably more effective fighting force than the Allies’, and there would be no victories until that changed. If British and French intelligence was poor in 1940, so was everything else.

As the Continent was evacuated, there was a late flurry of buccaneering by secret service officers and freelances: MI6’s Major Monty Chidson, a former head of the Hague station, rescued a priceless haul of industrial diamonds from Amsterdam. Peter Wilkinson got most of the Polish general staff out of France. Tommy Davies, a peacetime director of the Courtaulds textile business, escaped from its Calais plant with a load of platinum hours before the Germans arrived. But these little coups were fleabites in the great scheme of affairs. MI6 had made no contingency plans for stay-behind agents, to report from France in the event of its occupation by the Nazis, and Broadway would probably have been accused of defeatism had it done so. Through many months that followed, Britain’s intelligence services were thus almost blind to events on the Continent, to the frustration of the prime minister. Beleaguered on their island, they became dependent for knowledge of Hitler’s doings on the vagaries of air reconnaissance, and reports from neutral diplomats and correspondents.

The security service explored the limits of the possible and the acceptable in handling a stream of Abwehr agents who descended on Britain, and were promptly captured. MI5 spurned torture as a means of interrogation: in September 1940 at Camp 020, one of its officers intervened to prevent the captured Abwehr agent ‘Tate’ – Harry Williamson – being assaulted and battered by Col. Alexander Scotland of MI9. Guy Liddell deplored this episode, saying that he objected to ‘Gestapo methods’ on both moral and professional grounds. Col. Scotland was likewise prevented from injecting Williamson with drugs. Naval Intelligence Division interrogators tested drugs on each other as a means of extracting information, and concluded that it was a waste of time. Skilled questioning, they decided, was not merely more ethical, but more effective.

As the next act of the great global drama unfolded – Hitler’s air assault on Britain – neither Broadway nor Bletchley Park had much to contribute. The most significant aid to Fighter Command in its epic struggle to repel Göring’s air fleets was wireless traffic analysis of the flood of Morse from the Germans’ new French, Belgian, Dutch and Norwegian bases, together with monitoring of Luftwaffe cockpit chatter by the German linguists of the RAF’s infant Y Service, most of them women.

The prime minister and the chiefs of staff were for many months preoccupied, even obsessed, by two questions: would the Germans invade; and if so, when? In the mad mood prevailing in London in the autumn of 1940, a blend of heroic defiance and absurdity, the War Office’s director of military intelligence suggested exploiting captured Abwehr agents to try to provoke the Germans into hastening an invasion, which he felt sure could be defeated by the Royal Navy and the British Army. This proposal found no favour in Whitehall. Meanwhile the disaster in France had endowed the Wehrmacht with almost magical powers in the minds of the generals, many of whom convinced themselves that Hitler might launch an amphibious assault on Britain with only a few weeks’ preparation, offering no notice to the defenders.

The Royal Navy’s Commander Geoffrey Colpoys was responsible for delivering to Downing Street each day at 1 p.m. a report from the Special Invasion Warning Committee, which for most of the autumn took it for granted that a German assault was imminent, and concerned itself chiefly with the timing. The Joint Intelligence Committee, chaired by the Foreign Office’s Victor ‘Bill’ Cavendish-Bentinck, only once sounded the alarm to suggest that invasion was imminent, on 7 September, when, as Bentinck himself noted sardonically later, he himself was briefly absent and the army’s somewhat unstable director of intelligence – the same man who advocated inciting the Wehrmacht to land – temporarily held the chair. Churchill himself was always sceptical about an invasion, but he deemed it politically imperative to sustain the British people’s belief in the threat not only in 1940, but throughout the following year also, to promote their vigilance and sense of purpose. On 31 July Sir Alexander Cadogan expressed his own conviction that the Germans would not come, but would instead thrust at Gibraltar and Egypt, then added, ‘our “intelligence” gives nothing to corroborate this theory. But then they’re awfully bad.’ Nowhere in the world were British agents providing information of much assistance to the war effort. The British C-in-C in Singapore, Air-Marshal Sir Robert Brooke-Popham, wrote in frustration: ‘Little or no reliance is placed upon MI6 information by any authorities here and little valuable information appears to be obtained.’ The same was true nearer home.

For many months after the German occupation of Western Europe, the only nation still able to exploit secret sources on a large scale was the neutral Soviet Union, through its networks in Belgium, Germany and Switzerland. In those days its agents did not even need to trouble with wireless: they simply passed reports to their nearest Soviet diplomatic mission. In May 1940 the GRU’s Leopold Trepper moved from Brussels to Paris, taking with him his mistress, the exotically named Georgie de Winter, a twenty-year-old American, and leaving his deputy Anatoli Gourevitch to arrange the Trepper family’s return to Moscow. Gourevitch’s own personal affairs were scarcely uncomplicated. Under his cover as a ‘Uruguayan businessman’ he had a succession of girlfriends, but felt obliged to break off relations with the prettiest when she revealed that her father knew South America well. ‘In other circumstances,’ he wrote wistfully, ‘I could probably have loved her, but such good fortune is denied to a secret agent.’ Thereafter, however, he formed a friendship with a neighbouring family named Barcza, whose elderly Hungarian husband was married to Margaret, a much younger Belgian blonde with an eight-year-old son. Following her husband’s sudden death, Gourevitch began an intense affair with her. Mikhail Makarov, the other GRU career officer in Belgium, was also leading what Gourevitch described primly as ‘an excessively dissipated life’, in which prostitutes played a conspicuous role.

The German invasion of Belgium gave Gourevitch some bad moments: Brussels police arrested his supposed English friend and language teacher, who turned out to be an Abwehr agent; the man was promptly liberated when his compatriots overran the capital. The GRU network’s cover company ‘Au Roi’ collapsed when its Jewish frontmen fled and the business was sequestered. Moscow ordered Gourevitch to take over control of the Belgian operation. He entered Margaret Barcza on Centre’s books – allegedly without her knowledge – as a source unimaginatively codenamed ‘the Blonde’. The most believable aspect of his own later account of the whole saga is its emphasis on the rickety, rackety nature of a spy ring that history – especially Soviet history – has dignified as one of the great secret operations of all time. Gourevitch asserted that Leopold Trepper’s much-vaunted intelligence network in France and Belgium ‘was composed almost entirely of his old Palestinian friends’, and provided Moscow with no usable intelligence about Germany’s descents on Poland, Scandinavia or Western Europe. It seems unlikely that the Russians learned much more from its activities during the year that followed than Churchill and his generals gleaned from their morning papers.

In the absence of serious British military operations save in North Africa, secret war became a massive growth activity, impelled by the prime minister himself. Special Operations Executive was created in July 1940, to ‘set Europe ablaze’, while the armed forces spawned commandos, paratroopers and a string of ‘private armies’, notably in the Middle East. New recruits of all kinds flooded into Broadway, some of them exotic. ‘Writers of thrillers,’ wrote the supremely cynical Malcolm Muggeridge, ‘tend to gravitate to the secret service as surely as the mentally unstable become psychiatrists, or the impotent pornographers.’ Thus was Graham Greene dispatched to Freetown, Sierra Leone, Muggeridge himself – a veteran foreign correspondent – to Lourenço Marques, in Portuguese Mozambique, and the journalist Kim Philby welcomed into Broadway. It became a source of dismay to career intelligence officers, protective of MI6’s reputation, that its wartime recruits who later commanded most public attention were all either mavericks or traitors.

Lacking its own agents on the Continent, Broadway turned to the European exile governments in London for assistance in identifying sources. The Poles began to build impressive networks in their own country, though they suffered grievously from the fact – then of course unknown to them – that the Germans read the ciphers in which they communicated with their agents. František Moravec and his Czech group achieved formal recognition as the intelligence arm of their government; MI6 provided them with wireless facilities and documents. The Czechs established a new base in three little adjoining suburban houses in Rosendale Road, West Dulwich, until these were destroyed by the Luftwaffe, then late in 1940 moved to a new building in Bayswater. MI6 did not, however, give them money. Moravec, after spending the last of the cash he had brought out of Prague, was obliged to negotiate a loan of £50,000, to pay his network’s outgoings of £3,000 a month. For some time he continued to receive East European material via Zürich – Captain Karel Sedlacek had served as Moravec’s station chief there since 1934, under cover as a newspaper correspondent; since he lacked any literary gifts he was obliged to pay a ghost to write copy in his name. The Abwehr’s Paul Thummel used the Czech officer as his link to London; when he was arrested by the Gestapo in March 1942, Moravec’s little group ran out of sources.

The British enjoyed one immense piece of good fortune following their eviction from the Continent: nowhere did the Germans capture people or documents that betrayed Allied progress in cracking Enigma. Between 1940 and 1944 many Frenchmen, including hundreds of thousands of servants of the Vichy puppet regime, collaborated with their occupiers. But Vichy’s military intelligence officers, and several Poles attached to them who were privy to the pioneering Enigma codebreaking operation, revealed nothing even later in the war, when they were exposed to enemy interrogation. The capacious nets cast across Europe by the Nazis focused overwhelmingly on hunting dissenters, not machines. In the early years of occupation, when most people in the conquered societies acquiesced in their fate, Berlin’s spies and policemen uncovered little to ruffle their masters’ complacency, and mercifully nothing that caused them to doubt the security of their own communications.

In the winter of 1940–41, none of the principal belligerents knew much more about each other’s affairs than they learned from studying the international press and watching such movements as they could see of the rival armies, navies and air fleets. Most of the successful codebreaking that was taking place was being done by the Germans, and especially by the Kriegsmarine’s B-Dienst. The British lacked power to accomplish anything save the feeding of their own people. Hitler prepared to launch the most dramatic and ambitious lunge of his career, the assault on the Soviet Union, an act that could only have been undertaken by a man either bereft of accurate intelligence about the economic strength of his intended victim, or recklessly indifferent to it.

2 SHADOWING CANARIS

The Germans had made themselves masters of Europe, and shown the Wehrmacht to be the most formidable fighting force in the world. By contrast, whatever the limitations of the British and other Allied intelligence services, those of Hitler’s Abwehr were incomparably worse. In the summer of 1940 the chiefs of the Nazis’ information-gathering machine toyed with a scheme to plant an agent on a wrecked ship off the English south coast, though they never came up with a credible notion of what such a hapless castaway might achieve there. They also discussed landing agents in Kent, who would be invited to scale the white cliffs, a plan that was frustrated by a shortage of spies with mountaineering skills. Meanwhile the Luftwaffe’s intelligence department misjudged every aspect of the Battle of Britain, from respective aircraft strengths and losses to target selection. In September 1940, following the interrogations of the first enemy spies landed in Britain, Kenneth Strong of War Office intelligence professed himself baffled. He could not reconcile his lifelong respect for German efficiency with the risible management of the Nazis’ espionage activities.

The Abwehr bungled the selection, training, briefing and equipment of agents for service abroad; seldom were they even provided with decent forged passports. It is hard to distinguish between reality and fantasy in the doings of its operational section, Abwehr II, because its war diary was compiled to impress higher authority, and thus included reports from agents who never existed, about operations that never took place. Its chief, Admiral Wilhelm Canaris, who was regarded for decades after the war as an important personality and even as a hero of the Resistance to Hitler, was in reality a temporiser who lacked both the moral courage to challenge the Nazis whom he despised, and the skills to run an effective secret service in their interests.

The first man to grasp this was not a German, but a young English historian with a disdain for mankind in general, and professional secret service officers in particular. The manner in which Hugh Trevor-Roper became not the nemesis of Canaris, but instead his shadow, is one of the more remarkable stories of the secret war. The brilliant, testy, supremely arrogant Oxford don who, while not homosexual, professed a deep dislike of women, had just written his first book, a study of Archbishop Laud which he often reread during the war years: ‘I am forever discovering yet more exquisite beauties, lurking unsuspected among yet profounder truths.’ He spent the years between 1940 and 1945 monitoring the wireless traffic of the Abwehr, first for MI5 then for MI6. Trevor-Roper lived and breathed Canaris and his organisation, except on days when he went foxhunting. In growing degree, and comprehensively from 1943 onwards, the English academic learned more about Germany’s intelligence services than any man in the Nazi high command knew – certainly more than Canaris himself, because Trevor-Roper could identify the Abwehr’s many false informants, controlled by the so-called ‘Twenty Committee’ of intelligence officers in London chaired by MI5’s J.C. Masterman. The young academic may have nurtured a private longing, not unusual among intellectuals, to show himself also a man of action. He was immensely respectful of a lanky though never-met cousin, Richard Trevor-Roper, owner of a small estate in Wales, who joined the RAF’s Bomber Command and served as rear-gunner to the dambusting VC Guy Gibson, winning a DFM and DFC before being killed in action on his fiftieth operation, aged twenty-nine.

In December 1939 Hugh Trevor-Roper, then twenty-five, was summoned from Merton College to work alongside Walter Gill, a lecturer in electricity who had achieved celebrity as college bursar by installing lighting in Merton’s quadrangles. During World War I ‘Gilly’ had served in an army wireless section in Egypt, where he ran an aerial up the Great Pyramid. He listed his recreations in Who’s Who as riding, wireless research and ‘rebuking sin’. Now he and Trevor-Roper formed the nucleus of the Radio Security Service, a branch of MI5 initially quartered in the cells at Wormwood Scrubs jail in west London. Day after day, Post Office operators, previously employed to catch unlicensed private wireless transmissions, scoured the airwaves for signals from enemy agents transmitting from Britain, whom it would then be the role of the Merton pair to scotch.

Gill and Trevor-Roper found themselves frustrated by the emptiness of the ether, or rather by the absence of such traffic as they sought. They were failing, so it seemed. Only slowly did they come to understand that this was not because their own eavesdroppers were incompetent, but because no German spies were signalling home. Finding their original function redundant, on their own initiative the two dons widened their researches: they began to gather intercepts from stations in Europe that used known Abwehr callsigns. One evening, in the flat they shared in the west London suburb of Ealing, over tea and biscuits they cracked an Abwehr hand-cipher – a lower encryption system used by Canaris’s bases for communications with out-stations and agents lacking Enigma machines. Trevor-Roper, a fluent German linguist, started to read its messages.

When this came to the notice of Alastair Denniston, chief of Bletchley Park, he was not amused. The RSS’s amateurs were told that they were meddling in matters of no proper concern to them. Denniston added crossly that the Abwehr material was unimportant anyway. In fairness, his dismay about the RSS’s freelancing reflected more than petty jealousy. Months, indeed years, lay ahead before Bletchley’s codebreaking operations achieved maturity, but from the outset it was obvious that if the Germans gained an inkling of what was being achieved, the game would be over. The more diffused was British cryptographic activity, the greater the risk of a leak. Broadway stepped in, to vent its own justified anger, when it was learned that Trevor-Roper’s report on Abwehr activities in North Africa was circulated to a distribution list that included the Post Office wireless section.

Gill and Trevor-Roper, stubborn and mischievous men both, persisted nonetheless; they were soon reading much of the Abwehr’s traffic with its out-stations. To the dons’ glee, even when Bletchley established its own cell to monitor the same Canaris links, it was RSS and not GC&CS which broke the next four hand-ciphers. In the spring of 1941 RSS acquired a new interception centre with American equipment at Hanslope Park in Buckinghamshire, and began to establish its own out-stations abroad. In the course of the war, the little service passed on a million signals to Bletchley.

MI6 eventually made a successful takeover bid for RSS, which was logical, given Broadway’s suzerainty over signals intelligence. Trevor-Roper found himself working with Stewart Menzies’ communications supremo, one of the secret service’s more exotic figures, Colonel Richard Gambier-Parry. The colonel was one of many luminaries of ‘secret shows’ who was able to exploit to his own advantage their freedom from accountability to a service hierarchy. Gambier-Parry established MI6’s communications centre at Whaddon Hall in Buckinghamshire, which he also made his personal residence. A keen horseman, he took over the pre-war owner’s pack of hounds and placed the huntsmen on Broadway’s payroll; on one notable occasion, the hounds in hot pursuit streamed through the security gate of Bletchley Park, arousing in the mind of a mounted spectator in the know about its activities an idyllic vision of the brutes gorging on half-digested decrypts. Gambier-Parry lived like a medieval baron. Trevor-Roper, who knew him as a fellow-foxhunter, marvelled: ‘In the world of neurotic policemen and timid placemen who rule the secret service, he moves like Falstaff, or some figure from Balzac, if not Rabelais.’ It should be added that for the rest of the war Gambier-Parry ran MI6’s communications with energy and flair.

Hugh Trevor-Roper became head of the intelligence section of MI6’s Radio Analysis Bureau, run by Felix Cowgill, a former Indian policeman. Cowgill intensely disliked his new junior, whom he deemed guilty of ‘irreverent thoughts and dangerous contacts’. The Oxford historian took it upon himself to go well beyond the production of raw intelligence, conducting evaluation and analysis in a fashion MI6 had always spurned, because it lacked officers clever enough to do such work. The RAB began to produce ‘purple primers’, local guides to Abwehr personalities and agents around the world, which soon ran to many pages. The bureau noted that the Italians, who before the war had enjoyed some notable intelligence successes, were now almost entirely dependent for material on the Germans, and thus acquired their weaknesses.

In the summer of 1941 Trevor-Roper acquired an assistant, twenty-one-year-old Charles Stuart, who had just left Christ Church with a First in history, and the two were joined by another Oxford man, Gilbert Ryle. Patrick Reilly, a gifted young diplomat who became Stewart Menzies’ personal assistant, thought their little cell ‘a team of a brilliance unparalleled anywhere in the Intelligence machine’. Trevor-Roper began to serve as secretary of the joint MI5–MI6 Wireless Committee, in which role he came to know almost everyone significant in the secret world. The peering, bespectacled historian became one of the outstanding British intelligence officers of the war. His mastery of German operations increased steadily, especially after Bletchley’s Dillwyn Knox broke into the principal Abwehr machine cipher in December 1941. While the chiefs of Broadway believed – more so following the Venlo fiasco – that their enemies’ intelligence officers were wizards of guile, from an early stage Trevor-Roper became convinced of the Germans’ institutional incompetence. As for the Abwehr’s chief, he said, far from being a masterspy Canaris was a lost little man drifting on the tides of fate.

Admiral Wilhelm Canaris came from a family of Rhineland industrialists. After service as a U-boat officer in World War I he became engaged in right-wing politics, while playing a role in rebuilding the German navy. A senior officer’s 1926 personal report extolled his skills at the military-political interface: ‘With the finest feel for foreign psychology and mentality, together with uncommon linguistic ability, he knows in exemplary fashion how to deal with foreigners (from the lowest to the prominent).’ Interestingly, however, other naval officers, including Erich Raeder and Karl Dönitz, disliked Canaris, thinking him sly.

During the early years of Hitler’s rule he ingratiated himself enthusiastically and successfully with the foremost Nazis. In 1935, aged forty-eight, he was appointed chief of Germany’s intelligence service, controlling both espionage abroad and counter-espionage at home, though Himmler ran his own domestic security service, the RSHA, under Ernst Kaltenbrunner, with the Gestapo as its enforcement arm. As Trevor-Roper noted, ‘All German politicians of consequence sought to set up their own information bureaus (just as they also sought to establish private armies) as additional supports for their personal authority; and it was essential to the purpose of these bureaus that their results should be the private property of their chiefs.’

The RSHA was no more efficient than the Abwehr, but it wielded more influence through its direct subordination to Himmler. MI6 noted that it achieved good penetration of neutral embassies in Berlin, which yielded useful information. Meanwhile, Canaris’s service had stations around the world and intelligence cells within every formation of the Wehrmacht. The admiral’s early years of office saw a dramatic expansion of his empire; he achieved a reputation for administrative efficiency and diplomatic skills, both in his handling of the Nazi hierarchy and in dealing with prominent foreigners. Until at least 1942, the service’s prestige stood high both inside Germany and abroad.

Canaris was instinctively secretive, even before he became a spymaster, and more so thereafter. Within the rambling warren of offices in a row of converted mansions on Berlin’s Tirpitzufer, where the Abwehr had its headquarters until it was bombed out in 1943, he seemed to glide almost invisibly from one room to another. So he did too on his frequent travels to other countries, especially Spain: a signed portrait of Franco, its dictator, adorned his office wall. He seldom wore uniform – an oddity in Nazi society, which was obsessed with fancy dress. He was elaborately courteous, not least to subordinates, and something of a hypochondriac who took too many pills. He relaxed by riding regularly and playing a smart game of tennis. His passion for animals was much remarked: he was followed around Abwehr headquarters by two dachshunds, to which he talked constantly. One of them once fell ill while Canaris was visiting Italy, and he telephoned at length to Berlin to discuss its condition. His Italian companions assumed that he was speaking in code about great issues of state, but his obsession with the dog was authentic. He often said that he trusted animals more than people; it was probably more accurate to say that he liked them better. In conversation, whether professional or social, he was a master of equivocation. Few people were ever sure what Canaris really thought, which was supposed by contemporaries to reflect his depth of character. More likely, it masked chronic indecision.

Although technically a branch of OKW, the Abwehr quickly became Canaris’s personal fiefdom. Throughout the war his men achieved considerable success in suppressing dissent and capturing Western Allied agents operating in Hitler’s empire, which did much to sustain the admiral’s standing in Nazi high places: Col. Franz von Bentevegni, who ran counter-espionage, was one of Canaris’s few impressive subordinate appointments. Yet the Russians were able to sustain their astonishing espionage activities inside Germany until 1942, and military leakages persisted until 1945, even if the huge matter of Germany’s broken codes lay beyond Canaris’s remit.

The agents his officers dispatched to gather information abroad were almost all unfit for the role. It is odd that Berlin never attempted to recruit spies to dispatch to Britain who might have passed for gentlemen. Even in 1940, the accent and manners of the upper class remained a passport to social acceptance in Churchill’s embattled island. The writer Cyril Connolly wrote an angry letter to the New Statesman complaining that when he himself was detained as a possible spy, he was immediately released when it was discovered that he had been educated at Eton. The experience of the Cambridge Spies, deemed beyond suspicion as members of the upper-middle class, suggests that if the Abwehr had dispatched to Britain a few Nazis with passable table manners and some skill as fly-casters or grouse-shooters, they would have been asked to all the best houses.

As it was, however, when two of Canaris’s key men, Col. Hans Pieckenbrock, the head of intelligence, and Col. Erwin Lahousen, head of sabotage, were sacked in 1943, this was no gesture of Nazi spite, made for political reasons; it was the consequence of their obvious incompetence and of their departments’ failure. German secret operations abroad deployed immense labour for negligible results. One of the Abwehr’s most notable recruits was naval lieutenant Heinrich Garbers. He was a vegetable farmer’s son, a passionate Nazi, who in 1938 had sailed across the Atlantic in a thirty-foot yacht, the Windspiel, which he constructed himself. Amid the Allied naval blockade, the Germans devised the notion of dispatching agents to far-flung places in sailing boats too humble to attract the attention of the enemy. In 1941 and 1942 Garbers made epic forays to South Africa and Namibia respectively. Thereafter he captained the little schooner Passim, which made two immense voyages at an average speed of six knots. The boat sailed under the name of the Santa Maria, and flew successively French, Spanish and Portuguese colours as Garbers deemed appropriate. In 1943 he carried three Abwehr men, codenamed ‘Walter’, ‘Fred’ and ‘Jim’, to Argentina, in what he afterwards described laconically as ‘an uneventful voyage of 65 days’.

In a nautical sense it may be true that nothing much happened, but relations on board were poisoned by the mutual loathing of Walter and Fred, while Jim was perpetually prostrate with sea-sickness, which cost him a drastic weight loss. The passengers were successfully delivered to a reception committee of Argentine sympathisers at Rio del Plata, who presented the Passim’s crew with coffee and oranges before the little vessel turned about and sailed home. Garbers, plainly a man of iron, seemed wholly untroubled by his experiences. He returned safely to Europe and received the Ritterkreuz. There is no evidence, however, that his passengers contributed anything to the Nazi war effort. Likewise, the Hungarian air force officer Count László Almásy crossed 2,000 miles of North African desert to deliver two agents to Egypt in May 1942, a remarkable achievement, and Almásy later inspired the novel and film The English Patient, though its version of this enthusiastic Nazi was fanciful. His passengers, however, did nothing on arrival to justify their epic journey. Nearer home, it became increasingly clear to the British monitoring the Abwehr’s wirelessed reports that its network of overseas stations and informants produced almost nothing that was both new and true.

As Trevor-Roper pursued his researches through the ever-growing harvest of Bletchley decrypts, ‘We soon became aware that “the little Admiral” was a far more complex and controversial character than we had supposed. As the incompetence of his organisation was progressively revealed to us, we discovered, or deduced, something of the politics in which he was involved, and we noted his feverish travels, in every direction, but especially to Spain, which distinguished him sharply from our own more sedentary chief’ – Stewart Menzies. For several decades after the war, Canaris was treated as a major figure of the era, the subject of several weighty biographies. The foremost element in the Canaris mythology was a claim that he had been a secret crusader against Hitler, who had given active assistance to the Allied cause. Several German writers energetically promoted this view, because their post-war society was desperate to identify virtuous men who had dared to raise their hands against the vast evil of Nazism, and suffered martyrdom in consequence.

It is now plain that such claims were unfounded. Until 1938 Canaris was an ardent supporter of the Nazis, and for years thereafter Hitler frequently used him as a personal emissary abroad. The admiral worked amicably with Reinhard Heydrich of the RSHA. The two families socialised: Frau Canaris and the executive planner of the Holocaust sometimes played the violin together. From 1939 onwards, the admiral became increasingly gloomy and nervous – colleagues noted him drinking heavily. Trevor-Roper regarded it as an absurd delusion that Canaris was the directing brain of ‘the other Germany’. The Abwehr’s chief, in his view, was a man of limited gifts, who confined his anti-Nazi activities to making his organisation a haven for officers who shared his rising distaste for Hitler and his supporters, and who resisted active complicity in the Nazis’ atrocities. Canaris’s fastidious nature recoiled from the coarseness of their conduct, perhaps more than from its insensate barbarity.

The only Abwehr officer known to have been a source for MI6 was Hans-Berndt Gisevius in Switzerland, a Prussian lawyer of giant physical proportions who served five years in the Gestapo and hated it, before transferring to the Ministry of Internal Affairs in 1938 and thence to the Abwehr. Canaris sent him to Zürich under diplomatic cover as vice-consul, and thereafter he passed information to Halina Szymańska, whom he knew was an informant for both British and Polish intelligence. Gisevius provided material for twenty-five reports dispatched from Bern to Broadway between August 1940 and December 1942, some of them citing Canaris’s professed opinions; also among his sources was Hitler’s finance minister, Hjalmar Schacht.

Szymańska, the conduit, was the formidable and beautiful wife of the former Polish military attaché in Berlin, and once dined with Canaris in Bern. Much of Gisevius’s material was accurate: in January 1941 Szymańska passed on his report about German aircraft stocks, together with the Abwehr man’s opinion that an invasion of Britain was ‘off’. In April she quoted Gisevius’s view, based on information from Schacht, that Hitler would invade Russia during the following month – which indeed was then his intention. But, as usual with intelligence, the German also passed on some rubbish: on 28 March 1941 he told Szymańska that German forces would not take the offensive in Libya – two days before Rommel launched a major onslaught.

Gisevius’s contribution, and those of a handful of his colleagues, scarcely made the Abwehr a pillar of Resistance against the Nazis. Its wartime shortcomings were the product of indolence and incompetence rather than of considered treachery. Canaris was a poor delegator, who chose weak subordinates. German intelligence had one notable success abroad, in suborning Yugoslav officers ahead of their army’s 1941 emergency mobilisation, in time to sabotage the process, but thereafter its espionage operations were uniformly unsuccessful. The admiral was nonetheless too much a German patriot actively to assist his country’s enemies. Like many such people of the time, he harboured muddled political views. A monarchist and a conservative, Franco’s Spain was his spiritual home; he travelled there as often as he could, not merely to visit the large Madrid Abwehr HQ at Calle Claudio Coello 151, but also to commune with like-minded Spanish politicians and grandees. The Abwehr’s ship-watching service in Spain, the Unternehmen Bodden, monitoring Allied movements through the Straits of Gibraltar with the aid of advanced infra-red technology, and reporting them to the Kriegsmarine and the Luftwaffe’s Air Fleet 1 in Italy, formed the most impressive element in the organisation’s overseas operations.

Yet if Canaris bears much responsibility for the shortcomings of Germany’s ‘big picture’ intelligence, he could never have run an honest operation under the dead hand of Hitler, any more than Moscow Centre could do so in the shadow of Stalin. Reports on the condition and prospects of the enemy were permitted to reach conclusions only within parameters acceptable to the Führer. This crippling constraint was symbolised by Hitler’s annotation on an important intelligence report about Russian agricultural conditions: ‘This cannot be.’ Kurt Zeitzler, chief of the army general staff, wrote on 23 October 1942, the eve of Stalingrad: ‘The Russians no longer have any reserves worth mentioning and are not capable of launching large-scale offensives.’ Himmler in 1944 declared without embarrassment that his first requirement from Germany’s intelligence services was not truth, but loyalty to the Führer. This was an important statement, the most vivid expression of the huge weakness of the Abwehr and the RSHA throughout the Second World War.

Historian Michael Handel has written: ‘Leaders in a democratic system are generally more inclined to consider a wide variety of options than those who have always functioned within authoritarian or totalitarian political systems. In authoritarian countries, where the climb to the top is an unrelenting struggle for power, habits of cooperation and openness are usually less developed … Tolerance for ideas that deviate from the “party line” … are seen as personal criticism.’ These features of almost all dictatorships crippled German intelligence activities beyond the battlefield, and sometimes also within it. Himmler’s deputy Reinhard Heydrich, for instance, was far more interested in using the RSHA as a weapon against the Nazi empire’s internal enemies than as a means of securing information about its foreign foes. Hitler never wished to use intelligence as a planning or policy-making tool. He recognised its utility only at a tactical level: the Nazis were strikingly incurious about Abroad.

Yet the fact that the Abwehr was an unsuccessful intelligence-gathering organisation did not mean that Hitler’s armed forces were blind on the battlefield: their access to tactical intelligence was generally good. In the first half of the war Germany’s wireless interceptors and codebreakers enjoyed successes which would today seem impressive, were they not measured against those of the British and Americans. The Wehrmacht had excellent voice-monitoring units, which in every theatre of war provided important information. ‘The Y Service was the best source of intelligence,’ said Hans-Otto Behrendt, one of Rommel’s staff in North Africa. In August 1941, aided by an Italian employee, two agents of the Sezione Prelevamento – the ‘extraction section’ of Italian intelligence – opened the safe of the military attaché’s office at the US embassy in Rome. They removed his codebook – Military Intelligence Code No. 11 – and photographed it. This enabled the Axis to read substantial traffic through the ensuing ten months, and proved a seriously significant intelligence break. In 1942 it had especially grievous consequences for Eighth Army in the desert, since the US military attaché in Cairo, Col. Bonner Fellers, reported in detail to Washington on British plans and intentions. A German intelligence officer paid generous tribute to ‘this incomparable source of authentic and reliable information, which … contributed so decisively during the first half of 1942 to our victories in North Africa’.

At sea, some of the Royal Navy’s ciphers were found aboard the British submarine Seal, captured off the German coast on 5 May 1940, owing to an extraordinary and culpable failure by the minelayer’s officers to destroy its confidential papers. The Kriegsmarine was able to read much of the Royal Navy’s North Sea traffic until August 1940, and some warship communications until September 1941. Throughout the first half of the war, the Kriegsmarine’s B-Dienst read the Royal Navy’s convoy codes, with grievous consequences for Allied shipping losses. Even where signals could not be decrypted, radio-traffic analysis enabled Axis intelligence staffs to judge enemy deployments remarkably effectively, at least until the second half of the war, when Allied commanders became more astute and security-conscious. Patrolling, air reconnaissance and PoW interrogations all provided streams of useful data to German operational commanders, as did open-source information – enemy newspaper and broadcast monitoring.

In the first phase of the war until 1942, while the Wehrmacht was triumphant on battlefields across Europe, these sources sufficed to tell its commanders all that they felt they needed to know about the world, and about their enemies. Victories masked the abject humint failures of the Abwehr. As long as Germany was winning, why should anyone make trouble about imperfections in the war machine? It was only when Hitler’s armies started losing that hard questions began to be asked about the Reich’s abysmal political and strategic intelligence. Hitler himself was, of course, much to blame, but Canaris exercised operational responsibility. The admiral fell from grace, though it was by then far too late – probably impossible, for reasons institutionalised in the Nazi system – to repair his corrupt and ineffective espionage organisation.

While anxious not to be a bad man, Canaris lacked the courage to be a good one. Far from being a substantial historical figure, he was a small one, grappling with dilemmas and difficulties far beyond his capabilities. Trevor-Roper professed to see a close resemblance between the admiral and Menzies, his British counterpart. Both men were conservative, honourable – and weak. By a trifling coincidence, Canaris had a mistress in Vienna whose sister was married to Menzies’ brother. Trevor-Roper came to regard the Abwehr as ‘a mirror image of [MI6], with many of the same weaknesses and absurdities … I recognised, across the intervening fog of war, old friends of Broadway and Whaddon Hall transmuted into German uniform in the Tirpitz Ufer or at Wannsee.’ The admiral did little to merit his eventual fate at the hands of Hitler’s executioners: he frequently talked treason, but did nothing to further it. Far from becoming a martyr to the cause of a ‘good Germany’, he was merely an incompetent servant of an evil one.

3

Miracles Take a Little Longer: Bletchley (#u4fc4ded5-8677-5eda-950d-acfe9e4567f1)

1 ‘TIPS’ AND ‘CILLIS’

In the winter of 1939, MI6 came under scrutiny and fierce criticism within Whitehall, intensified by the Venlo fiasco. Stewart Menzies, knowing the precariousness of his position as ‘C’, compiled a twenty-six-page document defending his service, in which he risked playing one card which might – and did – save his bacon. He promised his masters that the country was ‘about to reap the fruits’ of MI6’s liaison with Allied secret services in a fashion ‘which should be of inestimable benefits to the Air Ministry within a few weeks, and probably to the Admiralty within a month or two’. The significance of this vaguely expressed claim was that Menzies believed that Bletchley Park, with the help of the French and Poles, was close to cracking some German ciphers. Such successes could go far indeed towards compensating for MI6’s humint failure. His expectations would remain unfulfilled for much of the year that followed. Few even within the intelligence community dared to hope that Britain could emulate, far less surpass, the 1914–18 triumphs of Room 40. Admiral Godfrey, head of naval intelligence, wrote to Menzies on 18 November, saying that ‘whether or not Cryptanalysis will ever again give us the knowledge we had of German movements in the late war’, MI6 should exert itself to plant agents in enemy ports to report shipping movements. Godfrey did not seem to expect much from the codebreakers.

In peacetime, few nations commit their finest brains to national security. Brilliant people seldom choose careers in intelligence – or, for that matter, in the armed forces. A struggle for national survival alone makes it possible for a government to mobilise genius, or people possessing something close to it, in the interests of the war effort. The British, and latterly the Americans, did this more effectively than any other participants in World War II. A remarkable proportion of their nations’ brightest and best sooner or later found themselves performing tasks worthy of their talents – in higher army staff posts alongside the likes of Enoch Powell, John Freeman, Toby Aldington; in scientific or technical research; and especially in intelligence, which absorbed thousands of outstanding intellects from many walks of life. The outbreak of war enabled the German section of British military intelligence, for instance, to recruit such writers and academics as Noel Annan, Eric Birley and Alan Pryce-Jones. Annan, a Cambridge don who had only a passable acquaintance with German and French, observed wonderingly: ‘Within a week I was piecing together the reports of agents in the Balkans and the early stutterings of Ultra.’

Donald McLachlan, a journalist who served under Godfrey at the Admiralty, afterwards argued that all wartime intelligence departments should be run by civilians in uniform, because they are unburdened by the lifetime prejudices of career soldiers, sailors and airmen: ‘It is the lawyer, the scholar, the traveller, the banker, even the journalist who shows the ability to resist where the career men tend to bend. Career officers and politicians have a strong interest in cooking raw intelligence to make their masters’ favourite dishes.’ MI6 remained until 1945 under the leadership of its old hands, but most of Britain’s secret war machine passed into the hands of able civilians in uniform who – after an interval of months or in some cases years while they were trained and their skills recognised – progressively improved the quality of intelligence analysis. The Admiralty’s Submarine Tracking Room was directed by Rodger Winn, a barrister and future judge. Gen. Sir Bernard Montgomery’s chief of intelligence from Alamein to Luneburg Heath was the Oxford don Edgar ‘Bill’ Williams, latterly a brigadier. Reg Jones made himself a legend in scientific intelligence.

These men, and a few hundred others throughout the armed forces, spent much of the war exploiting and assessing information derived overwhelmingly from interception and decryption of the enemy’s wireless traffic. Bill Williams, who served in the Mediterranean until 1943 and in Europe thereafter, stated in an important 1945 report: ‘It must be made quite clear that Ultra and Ultra only put intelligence on the map.’ Until decrypts began to become available in bulk in 1942, ‘Intelligence was the Cinderella of the staff … Information about the enemy was frequently treated as interesting rather than valuable [though] of course this attitude varied according to the commander.’

Scepticism was often merited, because much material was downright specious. The 1940 war diary of the army’s Middle East intelligence section in Cairo included comically frivolous snippets: ‘All Hungarian cabaret artistes have been ordered to leave the country by the end of May.’ Data about the Italian army was scanty, so that on 9 August the section recorded: ‘The present location and organisation of Libyan troops in Eastern Cyrenaica is obscure.’ A despondent staff officer added a week later: ‘There has been no further reliable information of fresh [Italian] ground units or formations arriving in Libya from overseas.’ On 27 September, the British high command’s weekly intelligence summary included a paragraph on domestic conditions in Germany: ‘A neutral traveller to the Leipsic fair, whose personal observations are believed reliable, reports that relations between the [Nazi] Party and the Army are not good.’ Three months later, the head of MI6’s Political Section wrung his hands: ‘It is piteous to find ourselves in this state of ignorance’ about both Germany’s internal condition and economy.

Only when Allied warlords were empowered to read the messages being exchanged between enemy generals in the field and their higher headquarters was scepticism about the value of ‘intelligence’ replaced by increasingly fervent belief. Ultra forced commanders-in-chief, not to mention the prime minister, to treat senior intelligence officers with a respect they had seldom received in the pre-Bletchley universe. Brigadier Ian Jacob of the war cabinet secretariat said: ‘My impression is that once the Ultra business got well-established, Churchill didn’t look at anything else.’ Eisenhower’s intelligence chief Kenneth Strong wrote in 1943, in a memorandum on training staff officers: ‘We no longer depend on agents and cloak-and-dagger sources for our information. Modern methods have completely transformed intelligence.’

He meant codebreaking, of course, and in Britain the fountainhead of such activity was the Government Code & Cypher School at Bletchley. In the months following the outbreak of war, GC&CS expanded dramatically with the arrival of a stream of academics, many of them earmarked by its recruiters before the war. Though some were seconded from the armed forces, it was understood that there was no need to train the universities’ contingent to march, blanco webbing, and name the parts of a rifle. They remained their sallow, tweedy, pipe-smoking young selves when housed in lodgings around the dreary suburban town, and enlisted on the government payroll without uniform or ceremony. Twenty-year-old mathematician Keith Batey found his landlady demanding an assurance from his employer that he was not a despised ‘conchy’ – conscientious objector – before he joined the growing body of academics working on a task of supreme importance to their country, fulfilment of which might do something to assuage its shocking vulnerability. What was the task? Bletchley’s little band, 169 strong in 1939 including support staff, understood only that the nation’s enemies communicated in a multitude of codes and ciphers, vulnerable to interception. If even a portion of these combinations of numbers and letters could be rendered intelligible, information might be gained of priceless value to the war effort.

Nobody knew, in the beginning, whether a given message hijacked from the airwaves might be an order from Hitler for his armies to march on Warsaw, or a request from a Luftwaffe airfield in eastern Germany for a delivery of filing cabinets. Ahead of the codebreakers lay a mammoth menu of requirements which could only be addressed as mobilisation sluggishly made available ears, brains and hands to monitor the enemy’s frequencies around the clock, log some of his vast output of messages, fix the locations and possible identities of the senders – diplomatic, police, military, naval or air force. Then came the much greater challenge, of discovering what the messages meant.

All radio communications involved a trade-off between speed and security. At the simplest level, battlefield direction by land, sea and air required some voice linkage. This enabled the instantaneous passage of orders and information, at the cost of being overheard by anybody else who cared to tune to a given frequency. Crude security could be introduced by using coded callsigns in place of names and suchlike – during the Battle of Britain fighter controllers added 5,000 feet to indicated altitudes, to confuse eavesdroppers. But voice messaging was inherently insecure: sensitive information should never be passed verbally, though it often was.

Most military messages were instead wirelessed by Morse key. Low-level material could be rapidly encrypted under battlefield conditions by relatively unsophisticated personnel using so-called hand- or field-ciphers, usually involving groups of two or three letters or numbers – the Kriegsmarine employed twenty-seven variants. More sensitive traffic, issuing from higher echelons, was translated by machine-generated or manual ciphers, usually involving combinations of four or five letters or numbers. The British thought justifiably highly of the security of their Type-X machines, though they never had enough of them.* (#ulink_69655881-16d6-5703-885c-8e3fca7501d7) The Americans rightly trusted their Sigaba, a fifteen-rotor system.

For substantial periods between 1939 and 1943 the Germans broke some Allied codes, including those of the US State Department and military attachés, along with the traffic of several exile governments, notably the Poles and Free French. They sometimes also accessed messages of all three British services, including the RAF’s four-character cipher, and later had successes in attacking products of the US Army’s M-209 field-ciphering machine. It deserves emphasis that Allied code-security weaknesses, and enemy achievements in exploiting them, gave the Germans much more operational assistance than some Western historians acknowledge, especially in the Battle of the Atlantic. However, higher British, American and Russian communications defied enemy scrutiny: Nazi eavesdropping on transatlantic telephone conversations between Churchill and Roosevelt told Berlin little of value. Modern claims that the Germans broke into Russian higher ciphers deserve to be treated with caution: certainly from 1942 onwards, there is no evidence that Hitler’s generals profited from any such insights; if they had, they would have been less often deluded by Soviet deceptions.

Most German senior officers – though by no means all their cryptographers – were confident that Enigma ciphering machines, which scrambled messages by means of shifting rotors and a plugboard, and rendered them comprehensible only by a matching machine with identical settings, were immune to the attention of any enemy, and indeed to the workings of the human brain. It is unsurprising that in 1939 they discounted the possibility that electro-mechanical technology might dramatically accelerate exposure of the Enigma’s secrets, because it did not then exist. It is extraordinary, however, that such serene confidence persisted through six years that followed, even following the discovery that the Poles had broken some pre-war Enigma traffic, and several warnings from their own experts. Amazing hubris was expressed by the Wehrmacht’s last signals chief, Lt. Gen. Albert Praun, who preened himself before his Allied captors after the war ended: ‘The achievements of German communications intelligence … may speak in favour of the German type of intelligence organisation.’ His organisation, he said, ‘gave German commanders a hitherto unattained degree of [signal] security’.

The British breaking of the Enigma, then subsequently and separately of German teleprinter traffic, was a progressive, incremental operation which attained maturity only between 1943 and 1945, and was never uninterrupted or comprehensive: even at peaks, only about half of all intercepts were read, many of them too late to provide practical assistance ‘at the sharp end’. What was done at Bletchley Park was indeed miraculous, but the codebreakers were never able to walk on all of the water, all of the time.

The 1939–40 Phoney War conferred few benefits on Britain, but it granted GC&CS precious time to bolster its strength and refine its methods. Without mechanical aids Bletchley’s brainstormers made modest and delayed breaches in a small number of enemy ciphers. The Germans employed acronyms and codenames which took weeks or months for their enemies to interpret. The importance of what happened at Bletchley in the first two years of war was not that it enabled Britain’s generals to avert or arrest a disastrous run of defeats, which it certainly did not, but that it lit a candle of hope about what the codebreakers and their embryo technology might accomplish in the future. It enabled the directors of the war effort to lay upon the board a few scattered pieces of a vast jigsaw, which would be filled only during the Allies’ years of victory.

Bletchley Park – Station X, Box 111 c/o The Foreign Office – was a notably ugly Victorian pile of bastard architectural origins surrounded by fifty-five acres of trees and grassland, located fifty miles from London. It was purchased in 1938 to house GC&CS at a safe distance from German bombs by Admiral Sir Hugh Sinclair, then head of MI6; as legend has it, he used £7,500 out of his own pocket, but more plausibly he paid with secret funds under his control. Whatever MI6’s humint weaknesses, the service’s chiefs, especially Sinclair, deserve full credit for backing the establishment of Bletchley at a time when resources were desperately constrained. Work began at once on laying direct phone and teleprinter lines to London, and in the following year MI6’s skeleton team of cryptanalysts moved from Broadway to the Park, where they came under the orders of Alastair Denniston. One of his colleagues from the old Admiralty days, Dillwyn Knox, an expert on ancient Egyptian papyri, became an early Bletchley stalwart. The most prominent of the younger recruits were Gordon Welchman of Sidney Sussex College, Cambridge, Hugh Alexander, Stuart Milner-Barry, John Jeffreys – and Alan Turing.

This last, the twenty-seven-year-old son of an Indian civil servant and the product of an austere and emotionally arid childhood, had just returned from a stint at Princeton clutching one of his own creations, a so-called electric multiplier machine mounted on a breadboard. His headmaster at Sherborne had once written: ‘If he is to stay at a public school, he must aim at becoming educated. If he is to be solely a Scientific Specialist, then he is wasting his time.’ In the headmaster’s terms, Turing had indeed been ‘wasting his time’: he had evolved into a shy, narrow, obsessive. Noel Annan wrote: ‘I liked his sly, secret humour … His inner life was more real to him than actuality. He disliked authority wherever he was … [and] enjoyed games and treasure hunts and silliness … Turing was the purest type of homosexual, longing for affection and love that lasted.’ More even than by his sexuality and his often childlike immaturity, however, his tragedy was to be afflicted by the exquisitely painful loneliness of genius.

Other drafts of young academics followed, variously codebreakers and linguists, together with the first of what became successive waves of young women, who would play a vital role in the operations of ‘BP’. The first two of these were daughters of golfing partners of Denniston, reflecting the importance of personal connections in Bletchley’s recruitment process in the early days, before industrialisation became inescapable. Indeed, the whole wartime intelligence machine emphasised the cosiness of the upper reaches of British life. Oxford University Press was entrusted with responsibility for printing vast quantities of codes, maps and reports, because of its pre-war experience producing examination papers under secure conditions. The Admiralty’s liaison with OUP was handled by Margaret Godfrey, wife of the director of naval intelligence. The Royal Navy’s Topographical Photographic Library was housed in the basement of the nearby Bodleian Library, which eventually dispatched 300,000 images a month to operational areas. The World War I intelligence veteran Admiral Sir William ‘Blinker’ Hall introduced Godfrey, his modern successor, to the City of London banking giants Montagu Norman, Olaf Hambro and the Rothschilds, who helped to identify suitable recruits for the NID.

Candidates being scrutinised for Bletchley were often asked: ‘Do you have religious scruples about reading other people’s correspondence?’ Twenty-year-old Harry Hinsley was interviewed at St John’s College, Cambridge by Alastair Denniston and Col. John Tiltman, the senior codebreaker. They said: ‘You’ve travelled a bit, we understand. You’ve done quite well in your Tripos. What do you think of government service? Would you rather have that than be conscripted?’ Hinsley would indeed, and joined the Naval Section located in Bletchley’s Hut 4. Through the icy winter of 1939–40, such men and women wrestled with Enigma traffic. Working conditions were dismal, with staff muffled in overcoats and mittens. The first break into a Luftwaffe Enigma key – designated ‘Green’ – is thought to have been made on 25 October 1939. In December, by unaided intellectual effort Alan Turing is believed to have broken five days’ worth of old naval messages. By the end of March, the French – or rather, the Poles working at France’s Station Bruno – had broken twenty days’ worth of old signals and BP about thirty, all Luftwaffe traffic.

Turing was much more importantly engaged. He compiled a 150-page treatise on Enigma, studded with schoolboyish blots, deletions and illegibilities. While most codebreakers addressed each other by first names or nicknames, heedless of age and status, almost everyone knew Turing as ‘Prof’ rather than as Alan. When his Enigma study was circulated later in 1940, it became known as ‘the Prof’s book’. He also set about fulfilling his concept for a ‘bombe’, a primitive but revolutionary electro-mechanical device for exploring multiple mathematical combinations. This borrowed its name, though not its design, from the Polish ‘bomby’, and would be capable of examining the 17,576 possible wheel deployments for a three-rotor Enigma in about twenty minutes: the order for the first machine was placed in October 1939, and the prototype became operational six months later. Meanwhile, outside in the park, workmen sawed and hammered at an ever-widening array of low wooden buildings which housed the growing staff. Eventually, only administrators worked in the main building, where the telephone switchboard was established in the ballroom. In the huts, signals were shifted from one section to another on a small trolley pushed along a makeshift wooden tunnel.

Hut 8 attacked German naval traffic, which was then passed to Hut 4 for translation and processing. Hut 3 performed the same function for Wehrmacht and Luftwaffe traffic decrypted by Hut 6. The former would eventually play a pivotal role in Allied wartime intelligence, but in its early incarnation it had a staff of just four. Frank Lucas, who was one of them, wrote: ‘On a snowy January morning of 1940, in a small bleak wooden room with nothing but a table and three chairs, the first bundle of Enigma decodes appeared. [We] had no idea what they were about to disclose.’ A few score yards away, Hut 6 run by Gordon Welchman wrestled with army-Luftwaffe ‘Red’ key traffic, which was the first to be broken in bulk.

From the outset, pains were taken to disguise from all but the most senior operational commanders the fact that information was being gained from codebreaking. This gave an unintended boost to the prestige of MI6, and to that of Stewart Menzies in particular. When Reg Jones gave a disguised report based on an Ultra decrypt to the RAF’s director of signals, Air Commodore Nutting, the airman professed astonished admiration for the courage of the presumed spies who had provided the information, saying, ‘By Jove, you’ve got some brave chaps working for you!’ The ever-growing scale of the enemy traffic to be trawled was intimidating. It is a measure of the expansion of communications as a branch of warfare that by August 1943, 305,000 personnel among the Luftwaffe’s total strength of 2.3 million were employed on signals duties – transmitting, receiving or processing – and the same was true on both sides of the war, and of all armed forces.

At GC&CS there were inevitable personality clashes. Gordon Welchman, whose creative contribution became second only to that of Turing, and whose organisational skills were also priceless, found it hard to work with the highly-strung and fractious Dillwyn Knox, a contender for the hotly contested title of Bletchley’s star eccentric. A notoriously awful driver, Knox giggled: ‘It’s amazing how people smile, and apologise to you, when you knock them over.’ He sustained a stream of intemperate complaints and demands to Denniston, his old comrade from Room 40, about staff shortages, working conditions, low pay, together with the intrusion of and excessive authority conceded to non-cryptanalysts: service intelligence officers ‘who maul and conceal our results’. Knox was seriously ill with the cancer that would kill him in February 1943, but meanwhile he and Welchman bickered: the older man accused the younger of exceeding his narrow initial brief, and was also impatient of Turing, writing, ‘He is very difficult to anchor down. He is very clever but quite irresponsible and throws out a mass of suggestions of all degrees of merit. I have just, but only just, enough authority and ability to keep him and his ideas in some sort of order and discipline. But he is very nice about it all.’ Turing prompted mirth by joining Bletchley’s Home Guard because he was seized by an impulse to learn to shoot, then provoked the apoplectic rage of its colonel by absenting himself from parades once he had fulfilled this private purpose. His unworldliness could provoke real exasperation among those under relentless pressure to produce results. A colleague spoke of Turing’s ‘almost total inability to make himself understood’.

There were plenty of minor tantrums lower down the hierarchy, unsurprising when staff were performing stressful tasks through long hours in bleak working conditions. Angus Wilson, the later novelist, once vented such a storm of rage that a colleague said wearily, ‘Do stop it, Angus, otherwise we’ll put you in the lake!’ Wilson retorted defiantly, ‘Don’t worry, I’ll do it myself,’ and duly plunged into the water in front of the house; on another such occasion he hurled a bottle of ink at a Wren. Many wartime codebreakers suffered temporary or permanent physical or mental collapses, brought on by their work: William Friedman, one of America’s pioneer practitioners, underwent a nervous breakdown in January 1941 which incapacitated him for three months. Hugh Trevor-Roper languished for several months at about the same time, and others regularly succumbed.

German signals were at first intercepted by a battery of army wireless-operators stationed in an old naval fort at Chatham, a role later assumed by Gambier-Parry’s organisation at Whaddon Hall. In the early war years there were never enough operators, and both the RAF and the army were reluctant to acknowledge the priority of meeting GC&CS’s demands. Signals were brought in batches to Bletchley’s guardroom by motorcycle couriers, at all hours and often in dreadful weather, then distributed between the relevant huts. From an early stage, the codebreakers learned to identify German senders by the unencrypted preamble to their message texts, none of which was longer than 250 words. It was then a matter of sitting hunched over a deal table through the hours of a shift, pondering a jumble of numbers and letters from which only men – and Bletchley’s handful of women – with remarkable logical or mathematical powers might hope to extract fragments of meaning. ‘The ideal cryptanalyst,’ Stephen Budiansky has written, ‘was Beethoven with the soul of an accountant.’ When Christopher Morris was a new recruit to Bletchley he heard one of his senior colleagues, asked the requirements for the job, respond laconically, ‘Oh, I suppose a sharp pencil and a piece of squared paper.’ Morris himself thought that the main requisites – except at the exalted level of Knox, Turing, Welchman and later Max Newman – were ‘patience, accuracy, stamina, a reasonably clear head, some experience and an ability to work with others’.

They opened what became vast card indexes, stacked in shoeboxes along the sides of the huts, cataloguing enemy units, personnel, codenames, locations, abbreviations and military hardware; different Enigma keys were distinguished by colour – for instance, yellow, green, red and blue, respectively indicating Norway, Wehrmacht, army-Luftwaffe and air training codes. ‘When a new word came up in the message you were translating,’ wrote Hugh Skillen, ‘a new type of jet fuel, or machine part – you looked for it, and if it was not there, the indexer put it in with a reference time and date stamp.’ Bletchley’s meticulous record-keeping became a critical element in its triumphs.

For security reasons, the Park’s operations were rigidly compartmentalised, and there was little exchange of information or gossip between sections. Even Welchman remarked years later how little he knew about what colleagues were doing a few yards away from his own Hut. As the staff grew from hundreds into thousands, facilities lagged behind: a section head complained that two hundred men and women enjoyed the use of just one lavatory. The food in the Bletchley canteen was poor even by wartime standards. Former debutante Sarah Norton one night found a cooked cockroach in her meat: ‘I was about to return it to the catering manageress when my friend Osla, who had the appetite of a lioness with cubs, snatched the plate and said: “What a waste – I’ll eat it!”’ The nearest available delicacies outside the wire were to be found at the Station Inn in Bletchley town, which offered ox heart. Welchman recalled having to provide his own newspaper to wrap fish and chips at the local shop. The codebreakers worked around the clock in three rotating shifts, starting with 8 a.m. to 4 p.m. When the exhausted men and women cycled or took a bus through the blackout to their lodgings, they found few comforts: dim lighting, hot baths often rationed to one a week, draconian rules about inter-sex visiting.

It is deeply impressive that those who worked at Bletchley sustained such dedication while working day after day, month after month, in a drab world devoid of glamour, excitement, variety, glory and decorations. In Hut 3, the watch sat around a horseshoe table, translating deciphered signals, each one resembling a telegraph flimsy, forwarded from Hut 6. Ideally, decrypts were composed of complete German words, but often there were interruptions and corruptions in the texts, which demanded leaps of imagination from the linguists. William Millward recalled with shame a night when he invented a place named ‘Senke’, near Qatara in the North African desert – having forgotten that Senke was the German word for a geographical depression. Schoolmasters proved ideal as watch chiefs, wrote Peter Calvocoressi, because they were naturally meticulous: ‘If not satisfied, they would throw back a translation at even an eminent professor. It reminded me of Chief Examiners at “A” Level who would send back scripts to an Assistant Examiner to re-mark.’ No one could work at GC&CS who did not love brain games. There were dreary, idle yet sleepless lulls, when no traffic arrived for the watches to work on. Peter Hilton once used such a doodle time to compose a palindrome: ‘DOC NOTE, I DISSENT, A FAST NEVER PREVENTS A FATNESS. I DIET ON COD’.

Although Alan Turing was acknowledged as the highest intellect at Bletchley, its achievement was supremely a team effort; the creative input of some others, Welchman prominent among them, was almost as important as that of Turing. One night in February 1940, several months before the arrival of the first bombe, twenty-one-year-old Cambridge mathematician John Herivel was smoking a pipe before the fire in his billet, and concentrating furiously on encoded messages even as he drifted in and out of a doze. An inspiration struck him as he gazed with the mind’s eye at a German Enigma operator. He perceived such a man starting his morning’s work bored or weary or hungover, and thus not troubling to change the previous day’s ring setting on his machine before starting to cipher messages. Herivel scarcely slept that night, as he went on to deduce how such an act of carelessness might be detected, then exploited to break a message.

Welchman, who had supervised him at Cambridge, immediately saw the importance of this flash of insight, a marriage of mathematical brilliance to a grasp of human weakness. He told the young man fervently that he ‘would not be forgotten’, and indeed his inspiration became known as ‘the Herivel tip’. Dillwyn Knox had already identified another entry point to messages, rooted in operator errors and text settings – what the codebreakers christened ‘Cillis’ or ‘Sillies’. Welchman wrote later that Bletchley remained ‘entirely dependent on Herivel tips and Cillis from the invasion of France to the end of the Battle of Britain’. In other words, until the arrival of the bombes, codebreaking was being done by raw brainpower, without significant mechanical assistance: at this early stage, the British lagged behind their American counterparts in exploiting technology – both the US Army and US Navy codebreaking teams used Hollerith punched-card sorters, of a kind that only began to appear at Bletchley in May 1940, because chief codebreaker Col. John Tiltman had been sceptical about them. Ultra provided no important material during the summer of 1940, but several indications about the postponement of ‘Sealion’, the Nazi invasion of Britain, notable among them a September Luftwaffe message ordering the dismantling of air transport equipment at Dutch airfields.

Fred Winterbotham, the MI6 officer who eventually became overseer of the ‘Special Liaison Unit’ network which fed Ultra decrypts to commanders in the field, described the first bombe – christened ‘Agnus’, corrupted to ‘Agnes’ – as resembling ‘some Eastern goddess who was destined to become the oracle of Bletchley’. It was installed in Hut 11 on 14 March 1940, but suffered substantial teething troubles. Gordon Welchman made an important contribution to Turing’s creation by devising a ‘diagonal board’, an element introduced into the first really effective model, which came into service in mid-August. Agnes and its many successors were not computers, because they had no memory. They were instead electro-mechanical key-finding aids, six and a half feet high and seven wide, mounted in bronze-coloured cabinets, and containing thirty-six banks of high-speed electrically-driven Enigma replicas. Each bombe contained eleven miles of wiring and a million soldered contacts. Built by the British Tabulating Machine Company at Letchworth, they depended partly on components assembled in scores of local village halls, by casual workers who had no clue of the importance to the war effort of the twenty-six-way cables and other small electrical parts they contributed.

With the assistance of a clue or ‘crib’ – a vital identifying link, usually a codebreaker’s guess about the nature of part of a given signal – a bombe could test millions of mathematical possibilities for the settings of three Enigma rotors. Figuratively, Agnes and her kin were bloodhounds needing a slipper or handkerchief to take up a scent. If there was no ‘crib’, the bombe could not solve the key – but mercifully often, there was one. Subsequent machines, miracles of reliability given their continuous operation, were given their own names by the Wrens who manned them around the clock, usually those of warships – Warspite, Victory and suchlike. The bombes did not take in enemy cipher messages and disgorge them in fluent German. They were instead priceless accelerators, once the codebreakers secured an insight into the nature of a given signal or traffic stream. Also useful was a battery of British Type-X cipher machines, modified to match the behaviour of Enigmas, on which Wren operators tested speculative message solutions. One of the principal constraints on codebreaking, especially between 1940 and 1942, was that access to the scarce technology had to be apportioned between competing claimants of the three services, and there was never enough ‘bombe time’ to go around.

Throughout 1940, human brainpower remained the dominant element in Bletchley’s successes, which increased with every passing week. It was ‘the Herivel tip’, not bombes, that enabled the team to crack the army-Luftwaffe ‘Red’ key in May. The overwhelming bulk of enemy traffic read through the rest of the year – around a thousand messages a day – was that of the Luftwaffe, and until the end of the war air force material was accessed more swiftly than that of the other services. An important requirement for success was what the codebreakers called ‘depth’ – possession of sufficient messages in a given key to give them playing space for calculations and speculations.

Luftwaffe signals provided many clues to the Wehrmacht’s parallel activities, but in the early days interpretation was impeded by lack of understanding of German terminology and abbreviations. In September 1940, Bletchley broke some traffic from Göring’s pathfinder unit, KGr100, which enabled it to forecast the targets of several bomber raids. But warning was of little practical usefulness to the defenders when hard power, in the form of radar-guided RAF night-fighters, was lacking in both numbers and effectiveness.

As more bombes were built – by 1945 there were 211 of them – they were dispersed around the London suburbs as a precaution against an enemy air attack on Bletchley. The operators, chiefly young women of the WRNS, found long hours beside the hot, smelly, clattering machines extraordinarily gruelling, especially when they were obliged to use tweezers to adjust the delicate electrical wiring. Some girls were unnerved by the monotonous racket. One of them said: ‘It was like a lot of knitting machines working – a kind of tickety-clickety noise.’ They went home with their shirt cuffs blackened by a fine spray of oil from the bombes’ revolving drums.

Naval Enigma remained for many months impenetrable. This was partly because its system of eight rotors, of which three were used at any one time, posed greater difficulties than the army’s five, and partly also because the Kriegsmarine’s operators were more disciplined than their Luftwaffe counterparts, and committed fewer errors to provide openings for Bletchley. There was a brief spasm of success in late April 1940, when five days’ traffic was read, but thereafter more than a year elapsed – an eternity in the minds of those who wrestled vainly with the problem day after day, week upon week – before the big breakthrough. Denniston said gloomily to Frank Birch, a 1918 veteran of Room 40 who now headed the naval section: ‘You know, the Germans don’t mean you to read their stuff, and I don’t suppose you ever will.’ Alan Turing himself had been dallying with the Kriegsmarine’s traffic almost since his arrival at Bletchley. A colleague, Hugh Alexander, observed that he became engaged because nobody else seemed to be making headway, and in his remote fashion he was fascinated by the abstract challenge.

It was Turing who devised a new method christened ‘Banburismus’, employing long punched paper sheets manufactured in the town of Banbury, which assisted the first important breaks into Kriegsmarine messages by reducing the number of possible Enigma rotor orders to be tested from 336 to around eighteen. This system was introduced in the spring of 1941, just as British losses to U-boats began to become alarming. On land, the British in those days lacked power and opportunity to do much with such knowledge of the Wehrmacht’s movements as they secured, and there was a large element of luck about what messages were broken. In North Africa in early 1941, the British Army profited from some good sigint derived from eavesdropping on the Italians, but few Enigma messages were broken quickly enough to assist decision-making on the battlefield. At sea, by contrast, there was an early golden prize for GC&CS’s labours.

The impetus towards success was provided by a series of captures far out on the ocean, which dramatically increased Bletchley’s knowledge of the enemy’s naval communications. On 23 February 1941, British commandos raiding the Lofoten Islands seized the German armed trawler Krebs, from which spare rotors for a naval Enigma were recovered, though the machine itself had been thrown overboard. This ‘pinch’ prompted the Royal Navy to launch an operation explicitly designed to capture more Enigma material, targeting German weather-reporting trawlers between Iceland and Jan Mayen Island. On 7 May, a sweep by three cruisers located and seized the München – but too late to save its Enigma and associated coding data from the Arctic deep. On 25 June the navy caught its sister vessel the Lauenburg, again minus its Enigma, but with a useful haul of cipher material.

Hut 8 now had enough information to read some U-boat signals, but the seizure which opened the traffic to fluent decryption was the fruit of chance and high courage, rather than of design. On 9 May 1941 a convoy escort group attacked and forced to the surface Julius Lempe’s U-110. A boarding party from HMS Bulldog commanded by Sub-Lieutenant David Balme secured the submarine, prevented its sinking, and brought back to his destroyer pearls beyond price: documentation for current Enigma. Though U-110 later sank under tow – fortunately so, from a security viewpoint – the short signal book, officer ciphering instructions and other material reached Bletchley safely, and the secret of the submarine’s capture was preserved beyond the war’s end. An Enigma machine was also recovered, but perversely this was the least useful element of the booty, because Bletchley had one already, together with assorted rotors seized in other ‘pinches’. Within days, Hut 8 was reading a steady stream of German naval messages. Ralph Erskine, one of the foremost experts on codebreaking at Bletchley, believes that the Park was already close to reading the Kriegsmarine traffic, even without the U-110 haul. What is for certain, however, is that it was impossible to break the U-boat ciphers without the assistance of captured material, which would again become a vital issue later in the war.

The breakthrough into the Kriegsmarine ciphers came just too late to influence the pursuit of the Bismarck in the latter days of May 1941. Conventional direction-finding on the behemoth’s wireless transmissions, supported by air reconnaissance, were the key factors in enabling the Royal Navy to intercept and sink it on the morning of the 27th, though assisted in the last stage by decryption of a Luftwaffe signal revealing Brest as Bismarck’s destination. Thereafter, Bletchley produced a steady stream of messages that revealed U-boat positions and intended courses. The so-called Hydra cipher was laid bare, and other keys were progressively broken: the more the Park knew, the more it was able to discover. The flow of decrypts was never assured, however, and disturbing delays sometimes took place. ‘Huff-Duff’ – High-Frequency Direction-Finding – played an important secondary role in the location of U-boats. The outcome was a relentless shift in the balance of advantage in the Battle of the Atlantic through 1941 and into 1942. Here was a case where intelligence indisputably and importantly influenced events.

Bletchley was also reading a significant portion of Italian naval traffic. On 25 March 1941, one of the small number of women decrypters, nineteen-year-old mathematician Mavis Lever in Dillwyn Knox’s team – he was famously supportive of talented girls in a male-dominated institution – played a critical role in breaking a message which revealed that the Italian fleet would shortly put to sea to attack British convoys. The warning enabled the Mediterranean C-in-C Admiral Sir Andrew Cunningham to contrive an encounter off Cape Matapan during the afternoon and night of 28 March which ended in a striking victory for the Royal Navy. By dawn on the 29th, three cruisers and two destroyers had been sunk, while the battleship Vittorio Veneto was damaged, an outcome that deterred the Italian surface fleet from making any further attempt to interdict British troop movements to Greece.

Spring brought an increasing flow of decrypts about Wehrmacht operations in the Eastern Mediterranean. Senior officers strove to streamline the transfer of information from Bletchley to battlefields, so that material reached commanders in real time. One of the most significant intercepts, detailing German plans for the May 1941 invasion of Crete, reported ‘probable date of ending preparations: 17/5. Proposed course of operation … Sharp attack against enemy air force, military camps and A/A positions … Troops of Fliegerkorps XI: parachute landing to occupy Maleme, Candia and Retiomo; transfer of dive-bombers and fighters to Maleme and Candia; air-landing operations by remainder of Fliegerkorps XI; sea-transport of flak units, further army elements and supplies.’ Churchill personally annotated the flimsy: ‘In view of the gt importance of this I shd like the actual text transmitted by MOST SECRET together with warnings about absolute secrecy.’ This information was passed to Wavell and Freyberg, the relevant commanders, at 2340 on 6 May. The loss of the subsequent Battle of Crete, following the German invasion which began on the morning of the 20th, emphasised a fundamental reality about Enigma decrypts: they could change outcomes only when British commanders and troops on the ground were sufficiently strong, competent and courageous effectively to exploit them. Stuart Milner-Barry of Hut 6 said that he and his colleagues looked back on Crete as ‘the greatest disappointment of the war. It seemed a near certainty that, with … every detail of the operation spelt out for us in advance … the attack would be ignominiously thrown back.’

The Cretan signal, informing British generals of German intentions in time to respond, was an exception rather than a commonplace in 1941. Bletchley was able to provide an ever-growing flow of information about the deployments of the enemy, not least in Eastern Europe, most of it derived from Luftwaffe and army-Luftwaffe decrypts. Wehrmacht traffic stubbornly resisted penetration, but German railway codes provided information about – for instance – troop movements to Yugoslavia, Greece and Eastern Europe in the summer of 1941. Hitler’s looming invasion of the Soviet Union, the towering event of the war, was also the first great strategic development for which Ultra intelligence provided explicit warning. While Britain had no power to influence or impede Hitler’s Operation ‘Barbarossa’, it was clearly of the highest importance to Churchill and his generals to be able to monitor its unfolding.

It became a source of increasing frustration to the prime minister that British troops in North Africa failed to frustrate or defeat Rommel when they had not only superiority in men, tanks and guns, but also an ever-growing stream of information about German deployments and movements, for instance at Halfaya Pass in May. Churchill pored intently over his own daily file of Ultra material. When he read a decrypt reporting petrol stocks at various Luftwaffe airfields in Libya, he scrawled on it in his red ink: ‘CAS [Chief of Air Staff] How many hours flying can their a/c do on this – about? WSC.’ Air Chief Marshal Sir Charles Portal responded testily: ‘Unfortunately it is not possible to make any general deduction since the figures only relate to the stock at Benghazi. We do not possess complete figures for the supply and consumption of oil and petrol throughout Libya. All we know is that there are indications of an overall shortage which is limiting operations in the forward area.’ This problem was endemic when decrypts were fragmentary. Stewart Menzies performed an important service by dissuading the prime minister from fulfilling his frequent desire to dispatch raw Ultra direct to commanders-in-chief in the field, as he had done in the case of Crete. ‘C’ was surely correct, on security grounds, and also because decrypts that lacked the context of other intelligence could be highly misleading to untrained eyes.

On land, in 1941 Bletchley provided more guidance to strategy than to tactics: it gave Churchill’s high command an authoritative, though never comprehensive, picture of German deployments in every theatre of war. Ultra could do little to assist the RAF’s ongoing struggle with the Luftwaffe for mastery of the skies. Only the Royal Navy gained immediate advantage, both in the Mediterranean and the Atlantic. Nothing altered the fact that, until the worldwide balance of strength began to shift in the Allies’ favour in the latter part of 1942, the operational superiority of German and Japanese forces enabled them to keep winning victories. Bletchley was an increasingly important weapon, but it was not a magic sword.

The practices and disciplines of GC&CS evolved progressively, with many wrangles and turf wars along the way. Deputy director Nigel de Grey complained about the ‘very low standards of military behaviour’ prevailing in what was supposed to be a military establishment. But how could it be otherwise? Noel Annan wrote: ‘Many of the cryptanalysts who produced Ultra were agnostic, heterodox dons who did not set much store by the normal interpretations of patriotism and democracy.’ It was not easy to combine the discipline essential to the operation’s smooth functioning with sensitivity to the wayward and frankly eccentric character of some of its resident geniuses. Col. Tiltman wrote ruefully on 2 March 1941: ‘Cryptanalysts have to be handled delicately and do not take kindly to service methods of control, which are essential to the good working of signals.’ When the director of the Royal Navy’s women personnel visited the Park, she demanded indignantly: ‘Why are my Wrens working with civilians?’ WAAFs in the teleprinter room expressed resentment about taking orders from civilians. In December 1940 the War Office’s director of military intelligence staged a grab for Bletchley’s military output. Until 1941, the Admiralty tried to continue some cryptographic work under its own roof. In Hut 3, rows erupted between representatives of the three armed services. Stewart Menzies received a constant stream of complaints from rival interests, while Bletchley staff referred to Broadway without enthusiasm as ‘the other side’. One of the most durable criticisms of ‘C’ is that he was ever eager to accept credit for the achievements of the Park, while declining to engage with its chronic resource problems, which eventually prompted the October 1941 letter to Churchill signed by Turing and his colleagues pleading for more staff, that caused Churchill to send his famous ‘Action This Day’ message: ‘Make sure they have all they want on extreme priority.’ It is a serious charge against Menzies, that he was an absentee landlord of GC&CS.

Yet all this made mercifully little impact on the work of the codebreakers. Edward Thomas, a naval officer who worked at the Park, was impressed by the absence of hierarchical distinctions: ‘Despite the high tension of much of the work … anyone of whatever rank or degree could approach anyone else, however venerable, with any idea or suggestion, however crazy.’ Few people of any rank or status felt denied a voice – an unusually rare and privileged state of affairs in the wartime institutions of any nation. From 1941, the Cambridge scientist and novelist C.P. Snow became a key Whitehall intermediary, responsible for channelling suitable mathematicians and other scholars to Bletchley. GC&CS also employed thousands of humbler folk, recruited chiefly for their language skills. Its files record details of some RAF personnel interviewed, such as Leading Aircraftsman Berry, aged twenty-three, who had started training as a pilot but re-mustered owing to his conscientious objections to dropping bombs. His German language skills were graded only ‘B’, and the recruiters noted: ‘if interested in work might do well, but needs careful handling’.

LAC Gray was also ex-aircrew, ‘grounded as result of crash’, had ‘B’ grade Spanish. Cpl Hodges, aged twenty-six, was unfit for aircrew, ‘anxious to use his German “A”, in civil life worked in architect’s office’. AC1 Tew, a twenty-eight-year-old clerk, had German ‘A’, as well as some Spanish, French and Danish, acquired while working in his father’s leather-trading business. There was much snapping between Bletchley and the Air Ministry about the latter’s reluctance to grant commissioned rank to RAF men seconded to cipher or wireless interception duties. Group-Captain Blandy of the Y Service complained that such people were ‘picked individuals having considerable linguistic qualifications and a high standard of education … [Mere Aircraftsmen] and NCOs lack the necessary authority required to carry out their duties efficiently.’

Not all the personnel posted to Bletchley proved suited to its demands. A March 1941 report on an RAF officer returned to general duties after a spell at BP noted: ‘Although an excellent linguist, he does not appear to me to have any aptitude or inclination for the research side of the work. He had been relegated to clerical tasks, but did not seem thus to justify his pay.’ There were equally bleak verdicts on the performance of some women staffers lower down the hierarchy: ‘Wren Kenwick is inaccurate, very slow and not a bit keen on her work, not very intelligent. Wrens Buchanan and Ford are unintelligent and slow and seem unable to learn. Wren Rogers suffers from mild claustrophobia and cannot work in a windowless room.’ The report concluded: ‘The remainder … are doing most excellent work,’ but the selectors were urged to recognise the importance of the jobs the women were required to fulfil, ‘and not to send us too many of the Cook and Messenger type’.

Enfolded within their oppressive security blanket, Bletchley’s people lived, loved and largely played within their own community. Almost all were paid a pittance: nineteen-year-old mathematician Mavis Lever, one of ‘Dilly’ Knox’s team, initially received thirty shillings a week, of which she paid twenty-one shillings for her lodgings. When staff did escape into the world beyond the perimeter fence, the civilian status of the young men incurred dark suspicions among the uninitiated about their absence from any battlefield. The dramas and pantomimes performed by the Park’s amateur dramatic society became high spots in the annual calendar: Frank Birch, formerly of King’s College, Cambridge and now head of Hut 4, was celebrated for his appearances as the Widow Twankey in productions of the pantomime Aladdin.

By 1942, common sense had achieved some important successes in the Park’s management. Each section worked to its appointed head, irrespective of rank or lack of it. Cryptanalysis for all Britain’s armed forces was handled entirely at Bletchley and its Indian out-stations, a concentration of effort that neither Germany nor the United States ever matched. Gordon Welchman emerged as the foremost lubricator, curbing feuding; several notoriously stupid service officers were transferred out; the popular Eric Jones was appointed to head Hut 3. It was acknowledged that the civilian codebreakers must be ridden on the lightest possible rein, though the director was prone to occasional surges of authoritarianism.

On 1 February 1942, Admiral Karl Dönitz introduced a reflector or fourth rotor into the Atlantic U-boat service’s Enigma, with immediate and calamitous results for Allied fortunes in the Battle of the Atlantic: this imposed a twenty-six-fold increase in the range of possible settings, and blinded Bletchley. Sinkings soared. At sea, the Royal Navy was obliged to rely upon ‘Huff-Duff’ to locate enemy submarines until these approached within range of underwater detection by the Asdics of convoy escorts, which were impotent against night surface attackers. Breaking what was now designated the ‘Shark’ submarine key became the Park’s foremost priority, a challenge unresolved for nine frightening months, by far the most stressful period of the war for those engaged in the task. They knew, as they sat hunched over their labours in those austere huts, that at sea men were dying every day because of their failure – though no rational person would have called it such.

Also on 1 February, coincidentally, Alastair Denniston was pushed aside into a subordinate London role, to be replaced by his deputy, Edward Travis. In some measure this development reflected a clash of personalities – Denniston and Stewart Menzies disliked each other – together with the infighting characteristic of any large bureaucracy. But it was widely felt at Bletchley that its operational head was being overwhelmed by the strains of running an establishment that since the outbreak of war had increased fourfold in size, and many times that much in its importance to the war effort. Power struggles were unavoidable. Denniston was a good and kind man who had done many things well, but Bletchley had outgrown him. Travis, whose edicts were issued in a curious trademark brown ink, was generally considered a success in his new role, not least by such influential creative figures as Welchman. When another codebreaker, Ralph Bennett, returned that summer from detached duty in the Middle East, he found that the atmosphere had changed markedly: ‘I had left as one of a group of enthusiastic amateurs. I returned to a professional organisation with standards and an acknowledged reputation to maintain. Success was no longer an occasional prize, but the natural reward of relentless attention to detail.’

Throughout 1942, Bletchley’s activities were hampered by a desperate shortage of bombes, and thus by argument about their best employment. In January the army-Luftwaffe Hut 6 was receiving 1,400 intercepts a day, of which an average of 580 were broken, a proportion that slowly increased, reaching about 50 per cent by May 1943. Often no more than one three-wheel bombe was available at any given time to work on the Shark U-boat cipher, because the others of what was still only a handful of machines were committed to breaking army and air traffic. The codebreakers said later that they would have needed ten four-wheel bombes – which did not then exist – significantly to accelerate their progress. By November, a note of desperation had entered the Admiralty’s pleas to the Park about Shark. The Battle of the Atlantic, said the navy’s Operational Intelligence Centre, was ‘the one campaign which BP are not at present influencing to any marked extent – and it is the only one in which the war can be lost unless BP do help’. A critical breakthrough was imminent, however. On 30 October in the Eastern Mediterranean U-559 was attacked by an escort group, and forced to the surface by depth-charging. Tony Fasson, thirty-year-old first lieutenant of the destroyer Petard, along with Able Seaman Colin Grazier, hastily stripped naked and swam sixty yards to the stricken submarine, then hauled themselves into the conning tower. The crew had opened the seacocks before abandoning their boat, and the sea was flooding in even as the two men searched the control room with desperate urgency.