Secret Life of Bletchley Park - McKay Sinclair [21]
By the summer of 1939, as the Polish nation faced certain invasion, these Enigma experts, together with a small French contingent led by Bertrand, decided to share their knowledge with the British, in the hope that they might be able to help further. Conversely, the Poles had information that the British side needed very badly indeed. On 24 July 1939, British and French cryptographers went to meet their Polish counterparts at Kabackie Woods near Pyry, a few miles south of Warsaw. Among the British members of this party was Dilly Knox. With him was Alistair Denniston.
The meeting was vital. As Knox and Denniston would have been painfully aware, they had to get a serious head start before Britain and Germany were at war. In particular, there had been an unthinking assumption among many, before 1939, that Britain still enjoyed unchallenged global naval supremacy. It would soon become clear that this was no longer the case. Moreover, the German navy was even more security conscious than the army. While the army could use cables to transmit messages, ocean-going battleships were forced to use radio signals, all of which could be picked up by others. These signals had to be encrypted with real cunning.
By 1939, Knox had run into a dead end simply because of the internal wiring of the military Enigma – an extra dimension of difficulty, distinct from the code wheels themselves. The trouble was that the Germans could have used countless different combinations of wiring on the keyboard. However, on that day outside Warsaw, the Poles told Knox that the Germans had in fact followed the most obvious, alphabetic pattern: A to A, B to B – with, as Jack Copeland explained, ‘the A-socket of the plug-board connected to the first terminal inside the entry plate, the B-socket to the second, and so on.’5 This was by no means the solution to the Enigma problem – but it did provide a valuable chink of light.
To be told, after months of worrying away at the wiring problem, that the solution was in fact the most obvious one, apparently proved a little too much for the habitually unpredictable Knox. Initially, according to Denniston himself, Knox ‘raged and raved’ when back in the car to Warsaw, shouting that ‘the whole thing was a fraud’. As Penelope Fitzgerald noted, however, for Knox ‘it was a swindle, not because he had failed to solve it, but because it was too easy. Games should be worth playing.’6
In a letter written some years later, Denniston said: ‘our position became increasingly difficult as even Bertrand, who knew no English, was aware that Knox had a grudge against the Poles who, so far as Bertrand knew, had only been successful where Knox had failed …’ According to Hut 6 veteran John Herivel, too, Knox’s temper could easily have had the most terrible knock-on effect. As he later wrote:
If Knox had continued to be in such a bloody-minded and intransigent mood, the conference would have been wound up, the French and British delegations would have returned home empty-handed, the further breaking of Enigma by the method of Zygalski sheets would never have taken place, and the Red Luftwaffe code would have remained unbroken, so that the Allied High Command would have been deprived of what Nigel de Grey termed ‘the prime source of intelligence’ for the most of the time from May 1940 until the end of the war.7
But the wild storm that Denniston seemed to recall must have passed very quickly. In a taxi on the way back from that forest rendezvous on the second day, Knox started cheerily chanting: ‘Nous avons le QWERTZU, nous marchons ensemble.’ And in a letter written at the time, he stated crisply: ‘I think we may hand some bouquets to the Poles for their lucky shot.’
Luck or skill aside, the information about the wiring