The Secret Life of Bletchley Park (7 page)

The Polish triumph was extinguished a little later in the 1930s when the German army – now regenerated and strengthening, and keen to tighten its security – increased the number of code-letter wheels on the machine from three to five, thus increasing the huge number of potential combinations another tenfold. However, this setback was in part countered thanks to a valiant Frenchman called Major (later Colonel) Gustave Bertrand, who was working in close contact with the Polish mathematicians. ‘I think we should acknowledge
what the French did in the field of Enigma,’ says Mavis Batey. ‘And indeed how they really did work with us until the fall of France.’

In the early 1930s, Gustave Bertrand had been carefully monitoring Germany’s development of Enigma and the machine’s uses. Some years earlier he had made contact with a German spy (or traitor, as the Germans themselves would have put it) called Hans Thilo Schmidt. Schmidt supplied Bertrand with crucial Enigma documentation. He had come by such paperwork because he worked in the German Ministry of War.

This was not Bertrand’s only success. ‘When the Germans improved the plugboard of Enigma,’ says Keith Batey, ‘they sent out a manual. And the idiots actually gave a plaintext telling how one set up the machine and this manual gave you the answer. The Germans realised, and recalled the manual right away – but Major Bertrand got hold of one none the less. That’s what gave the Poles the entry they needed.’

The Poles devised two cipher-checking methods. One was a manual method, using ‘Zygalski sheets’, named after their inventor, mathematician Henryk Zygalski. These, in essence, were a series of twenty-six thick sheets, one for each of the Enigma’s possible sequences for the insertion of the machine’s rotors. The sheets had specially prepared grids printed upon them, twenty-six by twenty-six, letters of the alphabet on the outer edges with holes punched or cut through the squares in certain combinations. The principle was based on what were termed ‘females’ – letter positions that would be repeated in an enciphered message. The sheets would be placed on top of one another above an illuminated surface, and moved and rearranged in carefully calculated sequences until the number of lights shining through the holes was reduced to one light shining through one section or square; this in turn would reveal the particular Enigma ring-setting. As a method, it was both wildly cumbersome and impossibly time-consuming. But before the Germans made further adjustments to Enigma, it worked. The principle was later to be expanded at Bletchley by John Jeffreys.

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.’
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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.’
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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:

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 was vital. Knox telephoned the information through to Peter Twinn. It is said that by the time Knox returned to Bletchley, Twinn had worked out the wheel wiring from this information alone, and had set to work on a few messages sent and intercepted the year before.

‘I was the first British cryptographer to have read a German services Enigma message,’ recalled Twinn lightly, adding, ‘I hasten to say that this did me little if any credit, since with the information Dilly had brought back from Poland, the job was little more than a routine operation.’ And, he pointed out, ‘of course, reading a few scattered messages [from] a single day in 1938 was a whole universe away from the problems that lay ahead.’
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The Poles also presented the British with a replica of the Enigma machine that they had built. ‘Dilly always said that we owed a huge amount to the Poles,’ says Mavis Batey, though she is equally adamant that the work of Colonel Bertrand should be properly celebrated. ‘Bertrand really did a good deal, with his Pimpernel pinches [the acquisition of coding information from the Germans]. Until the fall, Bertrand had his own cipher bureau in Paris and we had constant traffic and all the correspondence, and whoever got the key out that day shared it. That went on right up until the fall of France.’

Elsewhere, Alan Turing had been quietly busy upon his own researches. And by December 1939, quite independently of Knox and his new Polish friends, he managed to break into five days’ worth of Enigma material. Though this was, by itself, hugely encouraging, the messages Turing had worked upon were old – pre-war in fact. Neither he nor any other codebreaker had yet managed to crowbar their way into current German traffic.

In the deceptive quiet of those early weeks and months of the Phoney War, there was still time for theorising and experimentation. ‘Some days it was actually very slack,’ says John Herivel of his workload at that time. ‘You wouldn’t get that many intercepts in at all.’ But as the season grew darker, even with all the clues and the help given by the Poles, the codebreakers knew they were facing an increasingly fearsome proposition.

It was not just the mentally exhausting prospect of facing, day after day, these groups of random-looking letters, trying to think from every conceivable angle of some logical formula that would
bring order to the chaos and make the letters resolve into language. It was also the knowledge that they simply had to succeed.

The Italians provided a little succour. It was discovered that they were still using the earlier commercial version of the Enigma system, which although ingeniously complex, was known to be breakable. Dilly, with his rods and his fillies, was kept furiously busy in the Cottage, formulating means by which the Italian codes could be cracked by hand. At about the same time – the first Christmas at Bletchley Park, the ducks flapping in the freezing waters of the lake – Knox was also looking over Turing’s plans for new ‘bombe’ machines – which were to prove revolutionary in their potential.

But another obstacle for Bletchley was the fact that the different arms of the German military used subtly different versions of the Enigma system. The army Enigma machine was already fearsomely complex; the naval Enigma, as the cryptographers knew, was quite a different proposition – more complex, with extra code-wheels and more disciplined settings, using strict tables. Denniston doubted it could ever be beaten. For some of the new recruits making their way in blithe ignorance to Bletchley Park in the early months of the war, this would be the overriding priority.

From the start, one of the disorientating elements about Bletchley for a new recruit was the ambiguity of its status. It seemed to be neither a military nor a civilian operation, but – especially in its earliest days – a curious blend of the two.

In other words, this was not an environment of uniform, parade grounds and drill. And as work gathered pace, and the responsibility for breaking codes was divided between services – army, air force, naval – and sectioned off into separate huts, the place remained curiously self-governing and self-disciplining. If you worked in Hut 8 on the naval Enigma, for instance, you answered to the head of Hut 8 and seemingly no one else.

This vagueness of structure, combined with the nature of the personnel that Bletchley Park acquired, was the cause of some initial discomfort and bewilderment in Whitehall. As veteran and historian Harry Hinsley wrote of the organisation of the Park:

Lord Dacre, then Hugh Trevor-Roper, was attached to Intelligence at the time and quite often passed through the Park. He was reported as saying that the early years of Bletchley were marked with ‘friendly informality verging on apparent anarchy'.

Perhaps the only parallel with the call-up to the military was that the summons for Bletchley was not questioned by anyone who received it. However, unlike the weeks of careful training that one received for military service – the weapons-handling, the exercises – Bletchley seems to have been something of a plunge pool. For the early codebreakers and linguists alike, there was an element of being parachuted straight in to their new lives with little in the way of instruction. There are those who recall short, intensive courses for beginners being held in a nearby school; according to others, there wasn't even that.

‘It was all pretty quick,' says John Herivel. ‘I think especially for those of us who arrived in the early days. I was shown the Enigma, and packed off to see Alan Turing and Tony Kendrick. They were, in a sense, my teachers.'

Oliver Lawn, who arrived a little later, found himself feeling quite gung-ho about the nature of the challenges that lay ahead. He recalls: ‘These were basically mathematical problems and I had been trained as a mathematician, to spend my life doing these problems. This was just another form of problem.'

According to Mavis Batey the whole thing was more random than that. She recalls with some amusement the startlingly hands-off
approach when she first joined Dilly Knox in the Cottage: ‘We were all thrown in at the deep end. No one knew how the blessed thing worked. When I first arrived, I was told, “We are breaking machines, have you got a pencil?”

‘And that was it. You got no explanation. I never saw an Enigma machine. Dilly Knox was able to reduce it – I won't say to a game, but a sort of linguistic puzzle. It was rather like driving a car while having no idea what goes on under the bonnet.'

Mathematician Keith Batey is amused to this day about his initiation to the new, esoteric world of Enigma: ‘I arrived with two other chaps from the maths tripos. We were greeted at the Registry and were immediately given a quick lecture on the German wireless network. And I didn't pay much attention because I was focusing on these highly nubile young ladies who were wandering about the Park.

‘Anyway, after twenty minutes of this lecture, which told us absolutely nothing,' continues Mr Batey, ‘we were handed over to Hugh Alexander, who was the chess champion. He sat us down in front of what later turned out to be a steckered Enigma, and he talked about it. It didn't have a battery, it didn't work. And then we were just told to get on with it. That was the cryptographic training.'