The Secrets of Station X Read Online Free PDF Page A

importance for us and the French have furnished us with documents which have assisted us but we are still doubtful if success can be obtained without further documents. During the coming meetings, we hope to show Mr X the lines on which we are working and make clear to him what other evidence we need in the hope that his agents may produce it.
    The liaison with the French brought GC&CS a number of interesting documents, Cooper recalled. Since they arrived via the MI6 station in Paris in the same red jackets the British secret service used for all its reports, the French contributions were nicknamed ‘Scarlet Pimpernels’. They included documents on how to use the machine as well as photographs showing the Stecker system and how it worked, Cooper recalled. They also suggested that the French were not working alone.
    They had not disclosed that they had other signals intelligence partners. But a Scarlet Pimpernel on the German Air Force Safety Service traffic had obviously been produced from material intercepted not in France but on the far side of the Reich. It gave data on stations in eastern Germany that were inaudible from Cheadle, but was weak on stations in the north-west that we knew well. Eventually, the French disclosed that they had a liaison with the Poles, and three-sided Anglo-Franco-Polish discussions began on the Enigma problem.
    Denniston, Knox and Foss attended a meeting in Paris in early January 1939 with the French and representatives of the Bureau Szyfrow , Polish codebreaking organisation. The British codebreakers had high hopes that the meeting with the Polish codebreakers would help them to find a way to break Enigma. But it was to be a major disappointment. All three sides appear to have been too cautious to give anything of valueaway with Denniston describing the conference as having been held in ‘an atmosphere of secrecy and mystery’. The French codebreakers explained their own method of breaking Enigma, which was even less refined than the basic system used by Foss in 1927. Knox described his improved version of Foss’s system, which used a process known as ‘rodding’. The Poles were under orders to disclose nothing substantive and explained only how lazy operators set the machines in ways that produced pronounceable settings, such as swear words or the names of their girlfriends. This was something the British had already worked out and it was a great disappointment that they had nothing more to add, Foss recalled. ‘Knox kept muttering to Denniston, “But this is what Tiltman did,” while Denniston hushed him and told him to listen politely. Knox went and looked out of the window.’
    Knox was dismissive of the claims made by both the French and the Poles, in the latter case wrongly but largely because the officer explaining them was clearly not a codebreaker himself and did not speak with any authority on the subject. Knox’s assessment of the Polish work was damning: ‘Practical knowledge of QWERTZU Enigma nil. Had succeeded in identifying indicators on precisely the methods always used here, but not till recently with success. He [the Polish officer] was enormously pleased with his success and declaimed a pamphlet, which contained nothing new to us.’
    The main problem for Knox was what he called ‘the QWERTZU’, by which he meant the way in which the letters on the keyboard of the Wehrmacht Enigma machines were wired to the letters on the wheels inside the machine, and he left the meeting in Paris none the wiser. One good thing did however come out of the January 1939 meeting. It became clear that the Poles were using mathematicians to try to break Enigma and, when they returned to the UK, Denniston recruited two mathematicians to assist Knox. One was Alan Turing, a 27-year-old fellow of King’s College, Cambridge, who began working part-time ,coming in on occasional days with the intention of joining full time when the war began. The other was Peter Twinn, a 23-year-old