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.
They found treasure: the second edition of the Wetterkurzschlüssel, or weather short signal book, for its Enigma. Having wrapped this and other documents in waterproofing, Fasson and Grazier handed them up the hatch to sixteen-year-old NAAFI canteen assistant Tommy Brown, who had followed in swimming to the U-boat. He in turn passed the packages to the crew of a whaleboat, which arrived alongside in the nick of time. Brown, a civilian, lived to receive a George Medal for his daring, but the two supremely dedicated British sailors pushed their luck by plunging once more into the submarine’s control room, possibly in the belief that that they might retrieve a cipher machine. Bletchley did not need this, for it had already reconstructed the wiring of a four-rotor Enigma: it was the signal books that mattered. U-559 suddenly vanished into the Mediterranean, taking with it Fasson and Grazier, both of whom received posthumous George Crosses. The captured documents reached Bletchley on 24 November, and made possible the critical break into the Shark key on 13 December, assisted by data from weather decrypts secured by Hut 10.
That day, the codebreakers teleprinted to the Admiralty’s Operational Intelligence Centre locations for twelve Atlantic U-boats. Their positions were by now a week out of date, but they sufficed to provide critical guidance about the Germans’ likely courses. Thereafter, Shark signals were frequently broken within twenty-four hours, though the delay sometimes extended to forty-eight. This was one of the indisputably decisive moments of the intelligence war. Once regular Shark decrypts began to flow through to the Royal Navy, the balance in the war at sea shifted dramatically. Though Hut 8 later suffered more delays and difficulties with Shark, never thereafter was British control of the Atlantic sea route seriously threatened, and U-boat sinkings soared.
Among much else remarkable about Bletchley were not its periodic rows and tantrums, but that the front-line codebreakers, whose average age was twenty-three, sustained such a degree of fellowship. Derek Taunt described how they felt ‘devoted to the task of outwitting the enemy and happy to be part of a complicated organization designed to do just that’. Rolf Noskwith paid tribute to what he described as the Huts’ ‘exemplary leadership’. The integrity of the decoding operation was much assisted by the personal friendship between Stuart Milner-Barry of Hut 6 and Hugh Alexander of Hut 8. But tranquillity could never be attainable when thousands of men and women were working under appalling pressure around the clock, month upon month, year after year, knowing that lives depended upon their efforts. On 15 May 1943 Welchman wrote to Nigel de Grey, apologising for an explosion of rage during a discussion about organisation and shortage of resources, an ongoing bugbear. ‘My touchiness,’ he wrote, ‘is probably due to the fact that I always have the extreme value and urgency of our work very much on my mind. Throughout the whole history of Hut 6 there has never been a time at which I felt that we were being as efficient as we could be and you can imagine that this has been a heavy and continual strain … The present situation is an absolute scandal, but there is nothing we lack now that has not been asked for again and again. So please forgive me for being somewhat bitter and ill-tempered.’
He added: ‘A great deal of the work is terribly monotonous and deadly dull, and this has a very serious effect on morale over a long period. Some of the girls are almost physically sick at the sight of a Type-X machine. Now, if our girls crack up as many have done, we are absolutely sunk, and no amount of belated assistance will save us … Incidentally, could you possibly persuade Travis to get [Air-Marshal Charles] Medhurst [RAF director of intelligence] and [the CIGS Gen. Sir Alan] Brooke to spend even one minute telling the girls that their work is important? Yours ever Gordon.’ But difficulties persisted in securing qualified personnel, not least because so few people in Whitehall had any inkling of the supreme priority of GC&CS’s work. When BP needed personnel to operate punch-card machines, its recruiters turned to employees of the John Lewis Partnership, the department-store chain which had personnel trained to use them. Astoundingly, after ten women had been selected, the Ministry of Labour insisted that they should instead be dispatched to do land work. An internal memo at the Park seethed: ‘The John Lewis episode is a disgrace.’ The girls were eventually released to GC&CS, but only after a bitter wrangle with the civil bureaucracy.
From the war’s first day to its last, security was an obsession of every Allied officer privy to the Ultra secret. In 1941 a certain Col. Gribble, who had served as an air liaison officer with the RAF in France in 1940, published a book entitled Diary of a Staff Officer, which caused near-hysteria when Whitehall noticed, because it contained references to unidentified ‘secret sources’. Gribble’s work had been passed by a censor who knew nothing of Bletchley Park. What if somebody in Berlin read it, and drew lethal inferences about the vulnerability of Germany’s ciphers? MI5 bought up and pulped 7,000 unsold copies of the book, trusting to luck that none of its existing buyers had German friends. Before the fall of Singapore in February 1942, the key local Ultra and Y Service personnel received priority for evacuation, as did their American counterparts on Corregidor two months later. Had they fallen into captivity, not only would they have suffered a ghastly fate alongside other British and Australian prisoners, and their rare skills have been lost, but the risk to Allied codebreaking was frightening if they were exposed to interrogation and torture.
Most of Bletchley’s staff displayed marvellous conscientiousness about secrecy, all the more remarkable among young men and women – Station X’s footsoldiers – performing humdrum functions. In 1941 a civilian doctor in Nottingham wrote to the GC&CS authorities, reporting that one of his patients, a Wren named Adele Moloney, was in bed with a high temperature, having overstayed her leave with symptoms of acute exhaustion. He wrote: ‘Miss Moloney has hypertrophy of the conscience to such an extent that she will not divulge the smallest detail of what she does, even though it is against her interests. As I find it difficult to believe that this young girl is on work which is so important that her doctor must have his hands tied by lack of knowledge, I thought I would write to ask for your comments.’ Bletchley responded blandly that ‘there is in the ordinary way nothing that we know of in the work that she does that is in any way likely to be prejudicial to her health. The same work is done by a large number of other girls, none of whom so far as we know have suffered in any way.’ But BP told the doctor that Miss Moloney’s discretion was not merely correct, but ‘highly commendable’, and so indeed it was.
There was much unease among the administrators about the security risk posed by the rolling population of cooks, cleaners and workmen who serviced Station X. A 1941 report reflected uneasily: ‘New faces are being sent daily from the Labour Exchange to Bletchley Park.’ A series of flagrant breaches in the spring of 1942 prompted a magisterial memorandum to all personnel from the Park’s senior security officer: ‘There have been recent instances among you of a spirit of such reckless disregard for the consequences of indiscretion as would seem to argue not only a condition of ignorance or folly, but a contempt for the laws by which each one of us knows himself to be bound. In one instance [a BP staffer] disclosed the nature of their duties within her family circle … [this] was repeated by one of its members in mixed company, actually at a cocktail party, whence it was duly reported to me. In another instance one of the most vital tasks in which the organisation is engaged was disclosed, possibly in a spirit of pride or ostentation, in an after-dinner conversation to the Seniors of this person’s old College, whence a report reached me … It would be a reflection on your intelligence to suppose that you do not realise … that an idle piece of boasting or gossip … may be passed to the enemy and cause, not only the breakdown of our successful efforts here, but the sacrifice of the lives of our sailors, soldiers and airmen, perhaps your own brothers, and may even prejudice our ultimate hopes of victory.’
If this broadside was fiercely worded, it was not in