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Authors: Michael Smith
The Secrets of Station X (4 page)
Knox was in fact very close to breaking Enigma and there was just one major thing that was holding him up, Twinn recalled.
What we did not know was the order in which the letters of the keyboard were connected to the twenty-six input discs of the entry plate. Dilly, who had a taste for inventing fanciful jargon, called this the QWERTZU. We had no idea what the order was. We had tried QWERTZU, that didn’t work. There are twenty-six letters in the alphabet. Our ordinary alphabet has them in a certain order, but the Germans weren’t idiots. When they had the perfect opportunity to introduce a
safe-guard
to their machine by jumbling it up that would be the sensible thing to do. After all, there were millions of different ways of doing it.
The introduction of mathematicians to help Knox in his
investigations
of the Enigma problem was fortunately not the only good thing to come out of that first meeting with the Poles in Paris in January 1939. Knox might not have been initially impressed with the Poles, but they were certainly impressed with him and specifically asked that he be present at a second meeting between the Polish, British and French codebreakers,
to be held at the
Bureau Szyfrow
, the Polish cypher bureau, in the Pyry Forest just outside Warsaw, in July 1939. It was only then that the Poles revealed the full extent of the progress they had made in reconstructing the
Wehrmacht
’s steckered Enigma machine.
The
Bureau Szyfrow
had broken a number of German codes during the early 1920s but the introduction of Enigma had left them unable to read the
Wehrmacht
’s messages. Their response was to recruit mathematics students and put them through a codebreaking course. Only three passed. Their names were Jerzy Różycki, Henryk Zygalski and Marian Rejewski. All three were recruited but worked initially on a part-time basis and it was only in September 1932 that Rejewski, the best of the three, was given the steckered Enigma machine and asked to solve it. By the end of that year, assisted by Enigma key lists obtained by the French from
Asche
, he had reconstructed the wiring mathematically, using permutation theory. By the beginning of 1938, assisted by the fact that the Germans were not changing the settings frequently, Rejewski and his colleagues were able to solve 75 per cent of the Poles’ intercepts of German Army Enigma messages. ‘We were decyphering every day and often at a record speed,’ he recalled.
In the autumn of that year, they began using
electro-mechanical
machinery known as
Bomby
– literally ‘bombs’, a name that derived from the ticking noise they made. The
Bomby
were used to identify ‘females’, repetitive letters in the Enigma keys, to break the messages. But the introduction, in December, of two additional wheels, allowing further different permutations of wheel order, brought the Polish successes to a halt. Rejewski succeeded in reconstructing the wiring of the two new wheels but the Poles no longer had enough
Bomby
to run through the much greater number of possibilities the new wheels had created. They needed help and believed the British could provide it, said Colonel Stefan Mayer, the officer in charge of the
Bureau Szyfrow
. ‘As the danger of war became
tangibly near we decided to share our achievements regarding Enigma, even not yet complete, with the French and British sides, in the hope that working in three groups would facilitate and accelerate the final conquest of Enigma.’
The Poles explained how they used the
Bomby
and the
Netzverfahren
or ‘grid system’ invented by Zygalski. These were lettered sheets of paper with holes punched in them to help to break the keys and wheel orders by identifying the ‘females’. But the introduction of the fourth and fifth wheels had meant they had to use far more
Bomby
and sheets than they could possibly produce. Knox was furious to discover that the Poles had got there first, sitting in ‘stony silence’ as they described their progress and produced a clone of the Enigma machine, reconstructed using the knowledge they had built up over the previous six years. But his good humour soon returned after they told him that the keys were wired up to the encypherment mechanism in alphabetical order, A to A, B to B, etc. Although one female codebreaker had suggested this as a possibility, it had never been seriously considered, Twinn recalled. ‘It was such an obvious thing to do, really a silly thing to do, that nobody, not Dilly Knox or Tony Kendrick or Alan Turing, ever thought it worthwhile trying,’ he recalled. ‘I know in retrospect it looks daft. I can only say that’s how it struck all of us and none of the others were idiots.’
A few weeks later the Poles gave both the French and British codebreakers clones of the steckered Enigma. Bertrand, who had been given both machines and asked to pass one on to the British, later described taking the British copy to London on the Golden Arrow express train on 16 August 1939. He stepped down from the train at Victoria station to find the deputy head of MI6 Colonel Stewart Menzies standing on the platform, swathed in smoke and wearing a dinner jacket on which was pinned the rosette of the
Legion d’Honneur
. Bertrand handed the machine over to Menzies with the words, ‘
Accueil Triompha
l
’ – ‘a triumphant welcome’.
As well as setting up the meetings with the French and the Poles, which would ultimately give the British the additional information they needed to break Enigma, Denniston began building up the organisation for war, touring the universities to search out academics, particularly mathematicians, linguists and classicists, with potential to become the new
codebreakers
his organisation would desperately need to first break the German cyphers and then keep on top of them. Sinclair got authorisation from the Treasury for the recruitment of ‘fifty-six senior men or women, with the right background and
knowledge
’ as well as thirty young female language graduates. Josh Cooper recalled:
It was often said, in the old GC&CS, that if we had another war we should have to mobilise the dons again. Denniston now went on a round of visits to the universities in order to sound out his former colleagues from the 1914–18 war, to find whether they would be prepared to rejoin in an emergency, and whether they could introduce him to other university teachers who might be useful and would be prepared to come. He dined at several High Tables in Oxford and Cambridge and came home with promises from a number of dons.
Denniston, who was by now fifty-seven, recalled that
it was naturally at that time impossible to give details of the work, nor was it always advisable to insist too much in these circles on the imminence of war. At certain universities, however, there were men now in senior positions who had worked in our ranks during 1914–18. These men knew the type required. Thus it fell out that our most successful recruiting occurred from these universities. During 1937 and 1938 we were able to arrange a series of courses to which we invited our recruits to give them a dim idea of what would be required of them.
The ‘territorial training course’ lasted about a fortnight; the first day was taken up with security indoctrination, after which the trainees visited a number of sections spending two or three days in each, with programmes arranged to suit the interests and qualifications of individuals. At the end of the course they were asked to say whether they would undertake to come to Bletchley on receipt of a telegram, and to say which section they would prefer to work with. Their pay was fixed at
£
600 a year with their colleges making up the balance of their normal salaries. The young female language graduates were not so fortunate, receiving just
£
3 a week.
Denniston is in many ways a tragic figure, never given the credit he deserved for his astute decision to work with the French, which led to the cooperation with the Poles, and to bring in mathematicians, a proposition that was never going to be welcomed by many of his more experienced staff. He would later be unceremoniously pushed aside and when he died in 1961 there were no obituaries pointing out the good work he had done for his country. But the work he put into
recruiting
academics, and particularly mathematicians, and preparing them to be called up on the outbreak of war showed a large degree of prescience and, as Cooper recalled, laid the
foundations
for the breaking of the Enigma cyphers that was to make such a major contribution to the Allied war effort.
It would I think be hard to exaggerate the importance for the future development of GC&CS. Not only had Denniston brought in scholars of the ‘humanities’, of the type of many of his own permanent staff, but he had also invited mathematicians of a somewhat different type who were specially attracted by the Enigma problem. I have heard some cynics on the permanent staff scoffing at this course; they did not realise that Denniston, for all his diminutive stature, was a bigger man than they.
Those recruited included Gordon Welchman, a 33-year-old
mathematics lecturer and fellow of Sidney Sussex College, Cambridge, who would bring in a number of his students. Other more distinguished academics recruited to work at Bletchley included Professor Leonard Forster, a distinguished scholar of German and Renaissance Studies from Selwyn College, Cambridge; Norman Brooke Jopson, Professor of Comparative Philology at Cambridge, who was said to be ‘able to converse in most of the living languages of Europe’; Hugh Last, Professor of Ancient History at Brasenose College, Oxford; Tom Boase, Director of the Courtauld Institute and Professor of History of Art at the University of London; W. H. Bruford, Professor of German at Edinburgh, who had also served in Room 40; Gilbert Waterhouse, Professor of German, Queen’s University, Belfast; A. H. ‘Archie’ Campbell, Barber Professor of Jurisprudence at Birmingham; and J. R. R. Tolkien, Professor of Anglo-Saxon at Oxford University, who – sadly perhaps for codebreaking but not for the world of literature – eventually elected to remain at Oxford and write
Lord of the Rings
rather than join his fellow academics at Bletchley.
Patrick Wilkinson was one of those swept up by Denniston in his tour of the universities.
One day in the summer of 1938, after the Nazis had taken over Austria, I was sitting in my rooms at King’s when there was a knock on the door. In came F. E. Adcock, accompanied by a small, birdlike man with bright blue eyes whom he introduced as Commander Denniston. He asked whether, in the event of war, I would be willing to do confidential work for the Foreign Office. It sounded interesting, and I said I would. I was
thereupon
asked to sign the Official Secrets Act form. By now I had guessed what it was all about. It was well known to us that Adcock had been a member of Admiral ‘Blinker’ Hall’s Room 40 at the Admiralty in the First World War, famous since its existence was revealed in 1928, which had done pioneering work on the decoding of enemy messages. A totally secret
organisation, the GC&CS, had carried on in peacetime, under the Foreign Office since 1922, and was now run by Denniston, always known as ‘A.G.D.’, a retired naval schoolmaster, whom I sensed to be a kind and civilised man.
Adcock, who would himself join Cooper’s Air Section on the outbreak of war, had been involved in more surreptitious recruitment of some of his Cambridge colleagues for some time. E. R. P. ‘Vinca’ Vincent, professor of Italian Studies at Cambridge, recalled how Adcock summoned him to a discreet dinner in the spring of 1937.
We dined very well, for he was something of an epicure, and the meal was very suitably concluded with a bottle of 1920 port. It was then that he did something which seemed to me most extraordinary; he went quickly to the door, looked outside and came back to his seat. As a reader of spy fiction I recognised the procedure, but I never expected to witness it. He then told me that he was authorised to offer me a post in an organisation working under the Foreign Office, but which was so secret he couldn’t tell me anything about it. I thought if that was the case he need not have been so cautious about eavesdropping, but I didn’t say so. He told me war with Germany was inevitable and that it would be an advantage for one of my qualifications to prepare to have something useful to do.
Many of the young women were recruited in a way typical of the recruitment of clerks and secretaries into the intelligence services during the inter-war years. They were daughters of ‘somebody who knew somebody’. Diana Russell Clarke, a 25-year-old, whose father had worked in Room 40, was typical of the pre-war codebreakers recruited through family
connections
. ‘My mother simply rang up Commander Denniston, whom we’d known all our lives. She said: “Liza, have you got
a job for Diana?” He replied: “Yes, send her along,” so that’s where I started. We were on the third floor. There were MI6 people upstairs. They were always known as “the other side”. We didn’t have any truck with them.’
The signing of the Molotov–Ribbentrop Pact between the Soviet Union and Germany on 23 August 1939 left little doubt that war was now inevitable. Preparations were made to move to the MI6 ‘War Station’ at Bletchley Park, which was given the covername Station X, not as a symbol of mystery but simply because it was the tenth of a number of MI6 sites all designated using Roman numerals. Telegrams were sent out calling the dons to Bletchley and the existing members of GC&CS moved there on 15 August 1939.
Despite what now seems with hindsight to be the obvious imminence of war, the move to Bletchley in August 1939 was regarded very much as ‘a test’, similar to the visit of Captain Ridley’s Shooting Party the previous year. The memo ordering staff to prepare to move to the War Station said that ‘in order to carry out communications tests’ it would be manned from the morning of 15 August 1939 ‘by those detailed in GC&CS first wave’. From the outset the codebreakers and their support
workers
were told that there must be ‘absolute secrecy’ about what was going on at Bletchley Park, even among themselves. ‘The staff are warned against any conversations regarding the work with other members of the staff whilst in their billets. If occasion should arise as to what you are doing the answer should be that you are part of the aerial defence of London,’ the memo warned. It ended with the words: ‘This test is to be treated with absolute secrecy by all members of this department. Gas masks are to be taken.’