Then the sea war spread to the land, with the German attack on Norway forestalling British designs. The Anglo-French response was not helped by the fact that the German cryptanalytic department, the Beobachter Dienst, was able to read a number of their messages, as indeed they had been doing all the time since 1938, and that these were used with great effect. At the end of the campaign, the Commander-in-Chief of the Home Fleet complained that ‘it is most galling that the enemy should know just where our ships … always are, whereas we generally learn where his major forces are when they sink one or more of our ships.’ In the final withdrawal from Narvik, the aircraft carrier Glorious was sunk by the Scharnhorst and the Gneisenau on 8 June. The OIC did not know the position of the Glorious, let alone of the German warships, and learnt of the sinking from an open victory broadcast.
Norway brought Bletchley Park into the war, inasmuch as the main Luftwaffe key, and an inter-service key, were read ‘by hand methods’ throughout the campaign, and revealed a good deal about German movements. Even on the naval side, Hut 4 was able to do work on traffic analysis which could have helped with the Glorious. But there were no arrangements for putting the information to use – not that the conditions in Norway itself were such that it could have been used to much advantage. One negative achievement was that the OIC was now obliged to take some notice of Bletchley. The desperate need for better naval intelligence was now clear. ‘At the outset of the campaign the Admiralty’s own ignorance was complete. When it intervened to give the orders which resulted in the first battle of Narvik on 9 April, it did so in the belief, based on Press reports, that one German ship had arrived there, whereas the German expedition to Narvik had reached the port in ten destroyers.’
It was in this context that an almost miraculous chance of helping Alan’s work on naval Enigma was thrown away. For14
On 26 April the Navy captured the German patrol boat VP2623, while she was on passage from Germany to Narvik, and took from her a few papers … More might have been achieved if VP2623 had not been looted by her captors before she could be carefully searched; and the Admiralty at once issued instructions designed to prevent such disastrous carelessness in the future. As it was, except that they provided some information on the extent of the damage sustained by the German main units during the Norwegian campaign, the decrypts were of no operational use.
The capture of cipher hardware was to be expected and allowed for; the taking of flimsy, water-soluble pages* of current instructions for the use of the machine was a very different matter.
While the parliamentary upheaval meant that Winston Churchill now ceased to be responsible for this and other muddles, and instead took on the far greater muddle which was called the war effort, the ‘instructions designed to prevent such disastrous carelessness in the future’ were symbolic of an equally significant change. This time it would not do to have the military men behave as in some glorified Footer match, with the old masters giving earnest pep talks from the touchline, and back-room boys running dutiful errands. The lesson of the public schools was obsolete, for patriotism was not enough. They had to apply intelligence, at all levels, or they were lost. This was the conflict that would dominate the British war.
Meanwhile the work on the Luftwaffe Enigma, the Bletchley success of early 1940, was taking the first steps towards military usefulness. The steps were faltering, for on 1 May 1940, the ‘German authorities introduced new indicators on all Enigma keys except the Yellow’.* The perforated sheets had come only just in time to start off the treasure hunt; now they were almost useless. But there were ‘German mistakes in the few days after the change of 1 May’, very likely the classic one of sending out messages in both old and new systems. So by 22 May, Hut 6 was able to find out the new (‘Red’) system for the main Luftwaffe signals, and from that date to break it virtually every day thereafter. By that time, however, the German forces were at the Somme and closing on Dunkerque. The Bletchley success did not come soon enough to reveal German intentions during the first phase of the western attack. Indeed, ‘For a fortnight ignorance of what the enemy was up to was so great that, in the records of the Cabinet and the Chiefs of Staff, discussions of the fighting continued to be headed “The Netherlands and Belgium”.’ By the time they found out, it was too late to make any difference.
But it was now that the first Bombes came into operation – probably a Turing prototype in May 1940 and then more with the diagonal board after August. Naturally, the machines ‘greatly increased the speed and regularity with which GC and CS broke the daily-changing Enigma keys.’ The Bombes were installed not at Bletchley, but at various out-stations such as Gayhurst Manor, in a remote corner of Buckinghamshire. They were tended by ladies of the Women’s Royal Naval Service, the Wrens, who without knowing what they were doing and without asking the reason why, loaded the rotors and telephoned the analysts to say when a machine had come to a stop. They were impressive and rather beautiful machines, making a noise like that of a thousand knitting needles as the relay switches clicked their way through the proliferating implications.
Military officers attached to Bletchley were vividly impressed by the Bombes in operation. The secret service officer, F. W. Winterbotham, would refer to the Bombe as15 ‘like some Eastern Goddess who was destined to become the oracle of Bletchley’, and at the OIC, too, they spoke of ‘the oracle’. It was a usage that would have amused Alan, for he too had conceived of an oracle that would produce answers to unsolvable problems. What they began to discover, however, was that interpretation of the utterances was itself a major enterprise. If cipher machines had brought military communications into the Edwardian age, then the effect of the Bombes was to jolt military intelligence into the mass-production era.
In the First World War, Room 40 had worked hidden away in the Admiralty, its productions never coordinated with the results of sightings and interrogation. Only in the autumn of 1917, when the U-boat offensive was at its height, had the officer responsible for tracking them been allowed access to its information. The left hand did not know what the right hand was doing. And although the Navy’s cryptanalytic work had been16 ‘incomparably better than that of any other power, or of the British War Office’, Room 40 had operated in such a way that ‘there were no records, no cross-indexing, and what was not of immediate operational interest went into the waste paper basket.’
It was not until the fall of France, when the war ceased to be a re-run of 1915, that the Room 40 flavour began to give way. The Poles, Welchman, and Alan Turing had put a Bombe under the British establishment, and nothing could ever be the same again.17 ‘Based on a machine and broken on a machine, the Enigma’s cyphered mesages were mechanically converted direct into plain language; so that it yielded up its end-product in cornucopian abundance once the daily setting had been solved.’ Here was the opportunity to capture not just messages, but the whole enemy communication system. Indeed, it was essential to do so, for the ‘cornucopian abundance’ required a second level of code-breaking in order to interpret it:18
Apart from their sheer bulk, the texts teemed with obscurities – abbreviations for units and equipment, map and grid references, geographical and personal code names, pro-formas, Service jargon and other arcane references. One example is furnished by the fact that the Germans made frequent use of map references based on the CSGS 1:50,000 map of France. This series had been withdrawn from use in the British Army. Unable to obtain a copy of it, GC and CS was obliged to reconstruct it from the German references to it.
The Hut 3 filing systems, therefore, had to mirror the German system as a whole, in order to give meaning to the cipher traffic as a whole. Only when this had been done could the Enigma decrypts yield their real value – not so much in juicy secret messages, but in giving a general knowledge of the enemy mind. Without them, Europe was an almost complete blank, out of which anything could emerge. With them, they had some insight into what was possible.
No precedent existed for a ‘cornucopian abundanc
e’, and no means existed for making use of it. In 1940 the immediate problem was that of convincing anyone of the information thereby gained, without explaining its origin. At first it was passed off as the effects of spying. The result was that no military commander could take it seriously, since the offerings of the secret service were regarded as ‘80% inaccurate’. They had only just begun to consider more satisfactory arrangements for using the Luftwaffe decrypts in France, when events made the oracle irrelevant.
With customary British sang froid, those off duty at Bletchley Park played rounders in the afternoon as the news of the armistice came through.* Stern speeches and attitudes were of little help. In any case, it was radar that dominated the British eyes and ears in the coming months, although later in the year, gems of Enigma information provided clues to the Luftwaffe navigation beams. Radar, both in its technical development and in the communications network that it had forced upon the RAF, was three years ahead of Bletchley, an incoherent organisation whose time had not yet come.
Nor was there any pretence at heroism in Bletchley circles. It was not simply that Intelligence traditionally represented the most gentlemanly war work; not simply that the unspoken agreement was that of doing one’s bit while making as little fuss as possible. For at the higher levels, the cryptanalytic work was intensely enjoyable. Being paid, or otherwise rewarded, seemed almost a curiosity. It was also something of a holiday even from professional mathematics, for the kind of work required was more on the line of ingenious application of elementary ideas, rather than pushing back the frontiers of scientific knowledge. It was like a solid diet of the hard puzzles in the New Statesman, with the difference that no one knew that solutions existed.
Nor was there anything heroic about the scheme that Alan devised in 1940 for protecting his savings against imminent disaster. David Champernowne had observed that silver was one thing that had gained in real value during the First World War. Both he and Alan invested accordingly in silver bullion, but while ‘Champ’ prudently kept his in the bank, Alan typically decided to go the whole hog with a Burying Procedure.
Apparently he imagined that by burying the silver ingots, he could recover them after an invasion had been repelled, or that at least he could evade a post-war capital levy. (In 1920, Churchill and the Labour party had both favoured such a policy.) It was an odd idea. It was logical enough to be pessimistic about the outcome of the war, but if there had been an invasion, then surely some transatlantic evacuation of code-breakers would have taken place (just as the Poles had escaped to France), in which case he would have been better off with his savings in a form more suitable for transport. He bought two bars, worth about £250, and wheeled them out in an old pram to some woods near Shenley. One was buried under the forest floor, the other under a bridge in the bed of a stream. He wrote out instructions for the recovery of the buried treasure and enciphered them. At one point the clues were stuck in an old benzedrine inhaler and left under another bridge. He liked talking about ingenious schemes for coping with the war, and once proposed to Peter Twinn an alternative plan of buying a suitcase full of razor blades. It suggested the curious, but not totally impossible, picture of Alan as a street-corner hawker in a reduced Britain.
In August or September 1940 Alan had a week’s holiday, and spent it with Bob, making an effort to give the boy a treat. He had arranged for them to stay at what was for Alan a smart hotel, a renovated castle near Pandy, in Wales. It had been the usual hell for Bob in his first term, but, like Alan, he had survived the year, and at least had not encountered the usual public school anti-semitism. Alan asked a little about the past, and his family, but it was impossible to chat, for Bob had cast out the past as best he could, and Alan had no ability to heal such wounds. In fact, he probably never knew of the scenes which had taken place in Manchester as Bob pleaded unsuccessfully with the H——family to rescue his mother from Vienna.
They went fishing and for long walks over the hills. After a day or two Alan made a gentle sexual approach, but Bob rebuffed it. Alan did not ask again. It did not affect the holiday. Bob perceived that the possibility had been at the back of Alan’s mind from the beginning, but did not feel that Alan had taken advantage of him. He was simply not interested.
None of this was quite what Churchill had in mind when calling the British people to brace themselves to their duties, or speaking of the Empire that might last a thousand years. But duty and empires did not solve ciphers, and Churchill never bargained for an Alan Turing.
If the danger of direct invasion diminished, the attack on shipping was itself an invasion of the British metabolism. In the first year of war the sinkings by U-boats had not been the dominating problem. More significant were the disposition of the merchant fleets of newly occupied and neutral countries, the closure to trade of both the Channel and the Mediterranean, and the reduced capacity of British ports and inland transport to absorb whatever arrived.
From late 1940, however, the position began to clarify. The British-controlled merchant fleet had to supply an island separated by only twenty miles from an enemy continent, and to do so from bases thousands of miles across submarine-infested seas. Britain also had to continue the economic system on which vast populations around the globe depended and, to remain at war at all, had to attack Italy in a Middle East which was now as distant from Britain as was New Zealand. The lessons of 1917 had been applied, and a convoy system introduced since the outbreak of war, but the hard-pressed Navy could not escort convoys far into the Atlantic. And this time, Germany had achieved in a few weeks what four years of machine-guns and mustard-gas had sought to prevent. There were U-boat bases on the French Atlantic coast.
One factor alone weighed against the probability of German victory in the naval war. The U-boat force, so phenomenally successful in 1917, had not been built up in time for 1939. The bluffing over Danzig had meant that Hitler blundered into war while Dönitz commanded less than sixty submarines. Short-sighted strategy would keep the numbers at this level until late 1941. Although the sudden increase in U-boat successes after the collapse of France was alarming, it was not in itself a British disaster.
To remain capable of a belligerent policy Britain required imports of thirty million tons a year. A capital stock of thirteen million tons of shipping was available for this purpose. During the year after June 1940, U-boat sinkings were to deplete that stock by an average of 200,000 tons a month. This loss in capacity could just about be replaced. But anyone could see that a U-boat force just three times larger, enjoying a corresponding degree of success, would have a crippling effect both on the level of current supply, and on the total stock of shipping. Each U-boat was sinking more than twenty ships in its life-time, and there was no counter-strategy while the U-boat remained invisible. It was the logical, rather than the physical, power of the U-boat that was its strength. It was the German failure to follow up this tremendous advantage against its only remaining enemy that allowed a period of reprieve in which to counter this logical power with new weapons of information and communication. Radio direction finding and radar had already joined sonar in taking the Admiralty a short way beyond the resources of Nelson. The work of Hut 8 was still far behind.
Alan had begun his investigation of the naval Enigma messages on his own, but then was joined (for a time) by Peter Twinn and Kendrick. Clerical work was done by women who would be called ‘big room girls’. Then in June 1940 there was a new mathematical recruit: Joan Clarke, who was one of several ‘men of the Professor type’ to be a woman. The principle of equal pay and rank being stoutly resisted by the civil service, she had to be promoted to the humble rank of ‘linguist’ that the pre-war establishment reserved for women, and there was talk by Travis of her being made a WRNS officer so that she could be better paid. But in the Hut itself, a more progressive Cambridge atmosphere prevailed. She had just been reading for Part III, and was recruited for Bletchley by Gordon Welchman, who had supervised her for projective geometry in Part II. Her brother be
ing a Fellow of King’s, she had once met Alan in Cambridge.
So in the summer of 1940, Alan Turing found himself in the position of telling other people what to do, for the first time since school. It was like school inasmuch as the WRNS and the ‘big room girls’ played the role of ‘fags’, and because it meant meeting, or avoiding, members of the armed services. Alan’s methods for dealing with the clerical assistance, and other administrative problems, which gradually grew in scale, were like those of a shy school ‘brain’ who had been made a prefect by virtue of winning a scholarship. On the other hand, one notable difference from school was that it brought him for the first time into contact with women.
The rest of 1940 saw little progress with naval Enigma. The April U-boat capture, although largely wasted, had given them something to work on19 – and it was for this reason that Joan Clarke had been directed to Hut 8.
It had enabled GC and CS to read during May 1940 the naval Enigma traffic for six days of the previous month, and thus to add considerably to its knowledge of the German Navy’s [radio] and cypher organisation. GC and CS was able to confirm that, though the Germans resorted to fairly simple hand codes and cyphers for such things as light-ships, dockyards and merchant shipping, their naval units, down to the smallest, relied entirely on the Enigma machine. More important still, it established that they used only two Enigma keys – the Home and the Foreign – and that U-boats and surface units shared the same keys, transferring to the Foreign key only for operations in distant waters.
But only a further five days’ traffic, for days in April and May, were broken in the rest of 1940, and ‘the advance of knowledge had also confirmed GC and CS’s worst fears about the difficulty of breaking even the Home key, in which 95 per cent of German naval traffic was encyphered.’ Alan’s work showed that they could not hope for progress without further captures. But while they waited, he was not idle. He developed the mathematical theory that would be required to exploit them. There was far, far more to it than the building of Bombes.
Alan Turing: The Enigma: The Book That Inspired the Film The Imitation Game Page 32
