The Secrets of Station X (34 page)

The
Mincemeat
operation ahead of the Allied invasion of Italy in July 1943 gave an early taste of the usefulness of
Ultra
in the running and creation of deception operations. The campaign in Italy itself, with the Germans able to use
well-established
landline communications, provided far less scope for Hut 6 to become heavily involved. But the advent of the
Fish
teleprinter links and particularly the
Bream
link between Kesselring’s headquarters and Berlin provided a large amount of intelligence, not all of it limited to operations in Italy.

During the invasion of Europe, Bletchley’s involvement was absolutely vital across the board. The codebreakers’ ability to read the Japanese diplomatic and naval and military attaché cyphers and the
Jellyfish
encyphered teleprinter link from Paris to Berlin provided the vast bulk of the intelligence on the German defences and allowed Allied planners to ensure that the
invasion
plans had the greatest chance of success. The breaking of the high-level
Abwehr
Enigma messages which confirmed that the Germans believed the Double Cross Committee’s
deception
plan was absolutely critical to the success of the D-Day invasion and also assisted in
Operation Crossbow
, deflecting the V-weapons attacks on London.

Brigadier Bill Williams, Montgomery’s top intelligence adviser, credited
Ultra
with providing military commanders with the intelligence that would ensure the victory over the Germans.

At the end of the war in Europe, the Allied commander General Dwight D. Eisenhower wrote to Stewart Menzies, the head of MI6, asking him to pass on his ‘heartfelt admiration and sincere thanks’ to everyone at Bletchley Park ‘for the magnificent
services
which have been rendered to the Allied cause’. Eisenhower said he was only too aware of the enormous amount of work and effort involved in producing the
Ultra
intelligence and the setbacks and difficulties the codebreakers had faced down and overcome.

The achievements of the British codebreakers against Japanese codes and cyphers have been persistently underplayed. For many years, largely the result of a more lax US approach to releasing historical information, there was a general belief that the Americans broke the Japanese codes and cyphers. In fact we now know that, as with the Enigma and
Fish
cyphers, the British skill at making the initial breaks into the cyphers was mirrored in the Japanese systems. The Japanese introduced a whole stream of new codes and cyphers in advance of the war. John Tiltman had broken the new Japanese Army super-
encyphered
codes in 1938 and when the new Japanese Navy General Operational Code was introduced in June 1939, it was broken by Tiltman at Bletchley using material sent back by the British
Far East Combined Bureau in Singapore. This was the most important Japanese naval code of the war. Like the Japanese Army codes, it was ‘super-encyphered’ by adding streams of figures to the five-figure code groups.

British codebreakers based in Bletchley, Colombo, Delhi and for a while Kilindini in Kenya made the initial breaks into many of the main Japanese codes and cyphers. But while the British were the ‘break-in’ experts, getting into the codes and cyphers at the outset, the US had a far greater interest in keeping on top of Japanese codes and cyphers, as well as the ability to throw endless amounts of analytical machinery and manpower into the effort. This ensured that the Americans led the way in keeping on top of the Japanese codes and cyphers and therefore produced the great codebreaking coups of the Pacific War like the breaking of the Japanese orders for the Battle of Midway in June 1942, which was critical in the US victory, and the shooting down of the Japanese naval chief Admiral Isoruku Yamamoto in April 1943.

Quite aside from the codebreaking triumphs, there is the simple fact that Bletchley Park was the birthplace of the modern computer. The creation of
Colossus
was a tremendous
achievement
and if that was all that had happened at Bletchley Park it would still now be hailed as a demonstration of British
brilliance
. It is not for nothing that George Steiner, the philosopher and writer, has described Bletchley Park as ‘the single greatest achievement of Britain during 1939-45, perhaps during the [20th] century as a whole.’

So who were the very best of the codebreakers who worked at Bletchley Park? There were in fact so many great men and women working at Bletchley during the Second World War that it is invidious to make such a judgement, but even among the great names four figures do stand out above all the others. These were the truly great codebreakers.

Dilly Knox was a one of the leading experts in breaking hand codes and cyphers on the staff of the First World War
codebreaking
institution ‘Room 40’ and has never been given the proper credit for his role in ‘breaking in’ to the Zimmermann Telegram. After the First World War, he not only broke the cyphers used by Moscow to talk to its agents around the world, he also decyphered the
Mimiambi
of the Greek poet and playwright Herodas in his spare time. For most of the 1930s, Knox was probably the only person in British intelligence who believed the German Enigma cyphers could be broken. He broke into the less complex Enigma cypher machines used by Spanish Republican forces and their Italian allies during the Spanish Civil War and it was his ability and understanding of the machine that ensured that the Polish codebreakers felt able to share their own remarkable achievement against the pre-war
Wehrmacht
Enigma with the British.

Few people in the pre-war GC&CS shared Knox’s
confidence
that Enigma could be broken. Indeed, Denniston and Admiral Sinclair both believed it an unlikely feat. Without Knox it is likely that the vital wartime breaks into Enigma would have taken far longer to achieve. The breaking of the
Abwehr
Enigma, a feat deemed too costly in terms of time and manpower by Hut 6 and so abandoned by them, was a fitting climax to Knox’s career, and sixteen months after his untimely death in February 1943 would be a major factor in the success of D-Day. It is even possible that Knox’s work extended still further. In the months before his death, he was working at home on what are believed to have been Soviet high-grade cyphers, so he may even have had an influence on the codebreaking feats of the early Cold War.

The second name in this small group of the very best of the Bletchley codebreakers is John Tiltman, whose experience dated back almost as far as Knox’s – in Tiltman’s case to shortly before the creation of GC&CS in 1919. His ability to break anything from the Double Playfair type systems used by the German police troops carrying out the killings in Eastern Europe to
the high-grade machine cypher produced by the Lorenz SZ40 encyphered teleprinter system would set him apart even if he had never broken anything else. Tiltman’s hand is everywhere in the history of Bletchley Park, the first man on either side of the Atlantic to break JN25, the Japanese Navy’s main code system throughout the war, as well as several other main Japanese systems, including the Japanese Military Attaché’s cypher which was to be so productive on the German defences against D-Day. Tiltman was used against any code or cypher that no one else at Bletchley Park could break. His leading role in British codebreaking continued into the Cold War. Although we do not yet know what his full impact was, we know it must have been substantial because he continued to work for Bletchley Park’s Cold War successor GCHQ for a decade beyond the normal civil service retirement age of sixty and even then, at the age of seventy, was recruited by GCHQ’s US counterpart, the National Security Agency, to work for them as a
trouble-shooter
, yet again dealing with codes and cyphers that no one else could break. He died in Hawaii in 1982.

Many of the bright young mathematicians who joined GC&CS shortly before the war or once it had started were to distinguish themselves but none more so than Alan Turing. The inevitable interest in Turing as a result of his pioneering role in computing, which had an immeasurable impact on the world today from the small hand-held computers now seen
everywhere
to the internet, has tended to obscure and distort his role at Bletchley. Turing’s ideas on computing machines were undoubtedly highly influential on Max Newman, his former tutor, who initiated the use of computers to help break the
Fish
encyphered teleprinter systems. Turing was also involved in the discussions surrounding Newman’s proposals. But contrary to popular belief he was not involved in the Newmanry and the construction of the
Colossus
computer at all.

Like Knox, with whom he collaborated very closely in the initial attempts to break Enigma, Turing was a firm believer that
it could and would be broken. He took on the far more difficult Naval Enigma system, with its various complex security
measures
, when no one else dared try, justifying this ambitious move ‘because it would be so interesting to break it’. Hugh Alexander lauded Turing’s leading role in breaking the U-Boat cyphers, a feat that kept the supply convoys going and ensured British survival in the darkest days of 1940 and 1941 when the UK stood virtually alone against the Nazi threat.

‘There should be no question in anyone’s mind that Turing’s work was the biggest factor in Hut 8’s success,’ Alexander said.

Turing’s 1952 trial on charges of homosexuality, which ended his continued post-war links to GCHQ as a consultant, and his subsequent suicide in 1954 are now well-known. It was a truly tragic and bitter end to a life which produced so much and could have produced much more, giving added meaning to Alexander’s final comments.

The last of the four leading codebreakers to be singled out here is Hugh Alexander himself. Like Tiltman he continued to work for GCHQ as a codebreaker through the Cold War. At Bletchley, Alexander worked initially in Hut 6, then as Turing’s deputy and successor as head of Hut 8, before moving on to cover other problems as they emerged. When the Americans ran into
problems trying to break the Japanese naval attaché machine cypher
Coral
in the summer of 1943, Hut 8 joined the attack employing procedures used against the
Shark
Enigma. Led by Alexander, the British codebreakers began to make headway in September 1943 and, in February 1944, he flew to Washington to lead the final break in time for a major Japanese report on the German defences in Normandy to be decyphered ahead of D-Day. At the end of the war, Alexander initially went back to his previous work as Director of Research for the John Lewis Partnership but in mid-1946 decided to join GCHQ, becoming head of the codebreaking division in 1949 and refusing further promotion so as to remain at the coalface. Like Tiltman he was persuaded to stay beyond the standard civil service retirement date, retiring two years after his sixtieth birthday in 1971, and like Tiltman he was then approached by NSA to join them, an offer he declined. He died in Cheltenham in February 1974. Noel Gayler, the then Director of NSA, said Alexander had made a ‘monumental’ contribution to joint Anglo-American codebreaking operations and to ‘the special relationship’ between Britain and the United States. That ‘special
relationship
’ was in fact founded on the wartime cooperation between Bletchley Park and its US counterparts and the continued and extensive exchange of intelligence between Britain and the United States remains by far the most tangible evidence of its continued existence.

A list of codebreakers, intelligence officers and
administrators
who made substantial contributions to the work at Bletchley Park would be bound to omit others who also deserved
recognition
. Welchman’s invention of the diagonal board for the Bombe, for example, was absolutely vital, Tutte’s unpicking of the
Tunny
secrets astonishingly brilliant, but to continue the list would risk missing the point.