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- Herausgeber: Biteback Publishing
- Kategorie: Geisteswissenschaft
- Sprache: Englisch
- Veröffentlichungsjahr: 2011
The British codebreakers at Bletchley Park are now believed to have shortened the duration of the Second World War by up to two years. During the dark days of 1941, as Britain stood almost alone against the the Nazis, this remarkable achievement seemed impossible. This extraordinary book, originally published as Action This Day, includes descriptions by some of Britain s foremost historians of the work of Bletchley Park, from the breaking ofEnigma and other wartime codes to the invention of modern computing, and its influence on Cold War codebreaking. Crucially, it features personal reminiscences and very human stories of wartime codebreaking from former Bletchley Park codebreakers themselves. This edition includes new material from one of those who was there, making The Bletchley Park Codebreakers compulsive reading.
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Praise for Action this Day
‘Absolutely the best book ever written about codebreaking at Bletchley Park.’ Louis Kruh, Editor, Cryptologia
‘A sizeable contribution to the informed understanding of a world war.’ M. R. D. Foot, Times Literary Supplement
‘Peppered with priceless anecdotal and technical detail. Fascinating stuff.’ New Scientist
‘This gem … offers a pleasing combination of scholarship and memoirs.’ Mark E. Stout, The CIA’s Studies in Intelligence
‘Greatly extends our knowledge about the work done at BP [Bletchley Park].’ Jürgen Rohwer, Journal of Intelligence History
THE BLETCHLEY PARK CODEBREAKERS
HOW ULTRA SHORTENED THE WAR AND LED TO THE BIRTH OF THE COMPUTER
EDITED BY RALPH ERSKINE AND MICHAEL SMITH
Originally published as Action This Day: From the Breaking of the Enigma Code to the Birth of the Modern Computer – Bantam Press, 2001 (This edition is updated with a new chapter and additional material.)
CONTENTS
ACKNOWLEDGEMENTS
The editors are grateful to the contributors for so readily agreeing to donate their work to the Bletchley Park Trust (which is a registered charity), and for meeting a very demanding timetable without complaint.
Ralph Erskine is indebted to his wife, Joan, for her forbearance when he is engrossed in Sigint history, especially during the editing of this book. Michael Smith would like to thank his wife, Hayley, and his family for their patience. The editors found the project a rewarding one, and hope that readers will enjoy the result.
On 21 October 1941, four of the leading codebreakers at Bletchley Park wrote to the Prime Minister, Winston Churchill:
Secret and Confidential Prime Minister only Hut 6 and Hut 8, (Bletchley Park) 21st October 1941
Dear Prime Minister,
Some weeks ago you paid us the honour of a visit, and we believe that you regard our work as important. You will have seen that, thanks largely to the energy and foresight of Commander Travis, we have been well supplied with the ‘bombes’ for the breaking of the German Enigma codes. We think, however, that you ought to know that this work is being held up, and in some cases is not being done at all, principally because we cannot get sufficient staff to deal with it. Our reason for writing to you direct is that for months we have done everything that we possibly can through the normal channels, and that we despair of any early improvement without your intervention. No doubt in the long run these particular requirements will be met, but meanwhile still more precious months will have been wasted, and as our needs are continually expanding we see little hope of ever being adequately staffed.
We realize that there is a tremendous demand for labour of all kinds and that its allocation is a matter of priorities. The trouble to our mind is that as we are a very small section with numerically trivial requirements it is very difficult to bring home to the authorities finally responsible either the importance of what is done here or the urgent necessity of dealing promptly with our requests. At the same time we find it hard to believe that it is really impossible to produce quickly the additional staff that we need, even if this meant interfering with the normal machinery of allocations.
We do not wish to burden you with a detailed list of our difficulties, but the following are the bottlenecks which are causing us the most acute anxiety.
1. Breaking of Naval Enigma (Hut 8) Owing to shortage of staff and the overworking of his present team the Hollerith section here under Mr Freeborn has had to stop working night shifts. The effect of this is that the finding of the naval keys is being delayed at least twelve hours every day. In order to enable him to start night shifts again Freeborn needs immediately about twenty more untrained Grade III women clerks. To put himself in a really adequate position to deal with any likely demands he will want a good many more.
A further serious danger now threatening us is that some of the skilled male staff, both with the British Tabulating Company at Letchworth and in Freeborn’s section here, who have so far been exempt from military service, are now liable to be called up.
2. Military and Air Force Enigma (Hut 6) We are intercepting quite a substantial proportion of wireless traffic in the Middle East which cannot be picked up by our intercepting stations here. This contains among other things a good deal of new ‘Light Blue’ intelligence. Owing to shortage of trained typists, however, and the fatigue of our present decoding staff, we cannot get all this traffic decoded. This has been the state of affairs since May. Yet all that we need to put matters right is about twenty trained typists.
3. Bombe testing. Hut 6 and Hut 8 In July we were promised that the testing of the ‘stories’ produced by the bombes would be taken over by the WRNS in the bombe hut and that sufficient WRNS would be provided for this purpose. It is now late in October and nothing has been done. We do not wish to stress this so strongly as the two preceding points, because it has not actually delayed us in delivering the goods. It has, however, meant that staff in Huts 6 and 8 who are needed for other jobs have had to do the testing themselves. We cannot help feeling that with a Service matter of this kind it should have been possible to detail a body of WRNS for this purpose, if sufficiently urgent instructions had been sent to the right quarters.
4. Apart altogether from staff matters, there are a number of other directions in which it seems to us that we have met with unnecessary impediments. It would take too long to set these out in full, and we realize that some of the matters involved are controversial. The cumulative effect, however, has been to drive us to the conviction that the importance of the work is not being impressed with sufficient force upon those outside authorities with whom we have to deal.
We have written this letter entirely on our own initiative. We do not know who or what is responsible for our difficulties, and most emphatically we do not want to be taken as criticizing Commander Travis who has all along done his utmost to help us in every possible way. But if we are to do our job as well as it could and should be done it is absolutely vital that our wants, small as they are, should be promptly attended to. We have felt that we should be failing in our duty if we did not draw your attention to the facts and to the effects which they are having and must continue to have on our work, unless immediate action is taken.
A. M. Turing W. G. Welchman C H O’D Alexander P. S. Milner-Barry
We are, Sir, Your obedient servants,
On receipt of this letter, the Prime Minister minuted as follows to General Ismay on 22 October 1941 (reproduced in facsimile on the opposite page; PRO HW 1/155):
Secret In a locked box Gen. Ismay
Make sure they have all they want on extreme priority and report to me that this has been done.
WSC
22.x
DRAMATIS PERSONAE
Hugh Alexander joined Hut 6 in February 1940. He became deputy head of Hut 8 in March 1941, and its head during the autumn of 1942. He later worked on Japanese naval codes and cipher machines.
Gustave Bertrand was a member of French military intelligence, in its cryptology section. He supplied vital documents on Enigma to Polish intelligence and the Government Code and Cypher School (GC&CS).
Frank Birch joined the German naval section at Bletchley Park in September 1939, and later became the head of the naval section.
Joshua (Josh) Cooper joined GC&CS in October 1925 to specialize in Russian codes and ciphers, later becoming head of the air section.
Alastair Denniston was the operational head of GC&CS from its establishment until February 1942. He was then appointed the Deputy Director (Civil) (DD(C)) in charge of the section responsible for diplomatic and commercial codebreaking. He retired in 1945.
Thomas (Tommy) Flowers was the engineer at the Post Office Research Station who designed Colossus.
Hugh Foss joined GC&CS in December 1924. He devised a method to solve non-plugboard Enigma in the late 1920s, and was head of the Japanese naval section in 1942 and 1943.
William Friedman was the founder of the US Army Signal Intelligence Service (SIS), and its head until 1941. He was appointed the Director of Communications Research in November 1942.
Harold (Doc) Keen was an engineer at the British Tabulating Machine Company, which made the British bombe. He was responsible for the detailed design of the bombes.
Dillwyn (Dilly) Knox was the chief cryptographer (cryptanalyst) at GC&CS. He was severely ill from 1941 onwards, and died in February 1943. He specialized in breaking non-plugboard versions of Enigma.
Stewart Menzies (‘C’) became the head of MI6 in 1939 and, as such, was also the Director of GC&CS (Director General from March 1944).
Stuart Milner-Barry joined Hut 6 in early 1940, becoming its head in September 1943.
Maxwell (Max) Newman was the head of a GC&CS section known as ‘the Newmanry’, which attacked the Tunny cipher machine.
Marian Rejewski was the Polish cryptanalyst who first solved plugboard Enigma, in 1932.
Telford Taylor was a lawyer who joined US Army Intelligence in 1942. He made an extended visit to GC&CS in April 1943, and later worked in Hut 3.
John Tiltman was the head of the military wing at Bletchley Park, and GC&CS’s top cryptanalyst on non-machine ciphers. He was appointed chief cryptographer in 1944.
Alan Turing joined GC&CS in September 1939, and was head of Hut 8 until autumn 1942. He also worked on Tunny.
Edward Travis was a deputy to Alastair Denniston until February 1942, when he was appointed Deputy Director (Services) (DD(S)) in charge of the services’ side of GC&CS. He became the Director of GC&CS in March 1944 (when Menzies’s title was changed).
Gordon Welchman was the head of Hut 6 from its establishment until about the autumn of 1943, when he became the Assistant Director, Mechanicisation.
1
BLETCHLEY PARK IN PRE-WAR PERSPECTIVE
CHRISTOPHER ANDREW
Bletchley Park may well have been the best-kept secret in modern British history. The 10,000 men and women who worked there were, in Churchill’s famous phrase, ‘the geese who laid the golden eggs and never cackled’. Ultra, the intelligence produced at Bletchley Park from the breaking of high-grade enemy ciphers and the analysis of intercepted signals, was the best intelligence in the history of warfare. But if the secret had leaked out, Ultra would have been worthless. At the end of the Second World War most of those who had been ‘indoctrinated’ into Ultra believed that it would never be revealed. Not until the secret was declassified in the mid-1970s did the geese begin to cackle. A student at my Cambridge college told me how, together with his parents and his sister, he had watched the first BBC documentary on Bletchley Park which showed wartime Wrens (members of the Women’s Royal Naval Service) operating the ‘bombes’ used to break the German ‘Enigma’ machine ciphers. At the end of the programme, his mother turned to the rest of the family and told them, ‘That’s where I worked. That’s what I did.’ Until that moment neither her husband nor her children had had any idea that she had been a wartime codebreaker. The most extraordinary thing about this extraordinary episode is that, so far as the codebreakers were concerned, it was not unusual. Shortly before the publication in 1979 of the first volume of Sir Harry Hinsley’s official history, British Intelligence in the Second World War, he addressed a large reunion of Bletchley Park veterans and their spouses. After the address, the husbands of a number of former Wrens told Hinsley, ‘She never breathed a word to me.’
For the mostly youthful wartime recruits to Bletchley Park indoctrination into Ultra was an unforgettable emotional experience which had few, if any, previous parallels in the entire course of British history. Until their recruitment, hardly any of these people were even aware that Britain had a signals intelligence (Sigint) agency. Yet they suddenly found themselves, during Britain’s ‘finest hour’, in possession of a secret whose revelation might do irreparable damage to the war effort. No wonder that some, perhaps many, suffered from nightmares in which they unwittingly gave the secret away. The extraordinary success with which the Ultra secret was kept for so long reflected in part a national culture which embodied far greater respect for official secrecy and deference to authority than is imaginable today. Despite joining the anti-war movement only six years before he arrived at Bletchley Park, Alan Turing, one of the greatest of the wartime codebreakers, seems to have been untroubled even by peacetime doubts about the essential importance of official secrecy. During the Abdication Crisis of 1936, though at first ‘wholly in favour of the King [Edward VIII] marrying Mrs Simpson’, Turing had second thoughts after ‘It appeared that the King was extremely lax about state documents, leaving them about and letting Mrs Simpson and friends see them.’
In itself, however, a traditional national culture of official secrecy is an inadequate explanation for the extraordinary success with which the Ultra secret was maintained for so long. Some of the secrets of British codebreaking during the First World War had begun to leak out almost as soon as the war was over. In his great history of the war, The World Crisis, Winston Churchill, later among the staunchest defenders of the Ultra secret, vividly recalled his excitement while First Lord of the Admiralty for the first nine months of the war at receiving decrypted German naval radio messages which, on occasion, were delivered to him even in his bath, where he eagerly ‘grasped [them] with dripping hand’. During the 1920s, some of the early successes of Britain’s newly established peacetime Sigint agency, the Government Code and Cypher School (GC&CS), against the Soviet Union were revealed in both the press and government statements. Churchill’s own attitude to Sigint security at the time now seems remarkably naive. He wrote in the summer of 1920 that the ‘perfidy and treachery’ contained in Soviet diplomatic decrypts was such that their contents should be made public:
I have carefully weighed the pros and cons of this question, and I am convinced that the danger to the State which has been wrought by the intrigues of these revolutionaries and the disastrous effect which will be produced on their plans by the exposure of their methods outweighs all other considerations.
In September 1920, the Daily Mail and the Morning Post published details from the decrypts of secret Soviet subsidies to the socialist Daily Herald. In May 1923, the Cabinet authorized the Foreign Secretary, Lord Curzon, to quote Soviet diplomatic decrypts in a protest note to Moscow, chiefly concerned with Soviet subversion in India and India’s neighbours. The protest note, swiftly christened the ‘Curzon ultimatum’, was unprecedented in the history of British diplomacy. Not content with quoting from Soviet decrypts, Curzon repeatedly taunted Moscow with the fact that its secret telegrams had been successfully intercepted and decrypted by the British:
The Russian Commissariat for Foreign Affairs will no doubt recognize the following communication dated 21st February 1923, which they received from M. Raskolnikov … The Commissariat for Foreign Affairs will also doubtless recognize a communication received by them from Kabul, dated the 8th November, 1922 … Nor will they have forgotten a communication, dated the 16th March 1923, from M. Karakhan, the Assistant Commissary for Foreign Affairs, to M. Raskolnikov …
The new ciphers, introduced by Moscow in an attempt to make its diplomatic traffic more secure after the Curzon ultimatum and other British breaches of Sigint security in the early 1920s, were successfully broken by British cryptanalysts after varying intervals. In 1927, however, Britain’s ability to decrypt Soviet diplomatic traffic was fatally undermined by another extraordinary governmental indiscretion. The Baldwin Cabinet, of which Churchill was a member, decided to publish a selection of Soviet intercepts in order to justify its decision to break off diplomatic relations with Moscow. Austen Chamberlain, the Foreign Secretary, gave his message to the Soviet chargé d’affaires breaking off relations a remarkably personal point by quoting a decrypted telegram from the chargé to Moscow ‘in which you request material to enable you to support a political campaign against His Majesty’s Government’. A. G. Denniston, the operational head of GC&CS, wrote bitterly that Baldwin’s government had deemed it ‘necessary to compromise our work beyond question’. Henceforth Moscow adopted the theoretically unbreakable ‘one-time pad’ for its diplomatic traffic. For the next twenty years British cryptanalysts were able to decrypt almost no high-grade Soviet diplomatic traffic (though they continued to have some success with communications of the Communist International).
The lessons learned from the Sigint catastrophe of 1927, as a result of which Britain lost its most valuable interwar intelligence source, were crucial to the later protection of the Ultra secret. No politician took those lessons more to heart than Winston Churchill. After he became prime minister, at his personal insistence the circle of those who shared the secret of the cryptanalysts’ ‘golden eggs’ was limited to only half a dozen of his thirty-six ministers. The Special Liaison Units set up to pass Ultra to commanders in the field were the most sophisticated system yet devised to protect the wartime secrecy of military intelligence. The profound change in Churchill’s attitude to Sigint security is epitomized by the contrast between his published accounts of the two world wars. In his memoirs of the First World War, Churchill had written lyrically of the importance of Sigint; in his memoirs of the Second World War there is no mention of Ultra.
As well as being crucially dependent on the lessons learned in 1927, Ultra also owed much to precedents set in the First World War. The creation of GC&CS in 1919 was itself a consequence of the fact that Sigint had proved its value during the war. Without the expertise painstakingly built up by Denniston on minimal resources between the wars, Bletchley Park’s wartime triumphs would have been impossible – despite the invaluable assistance provided by the Poles and French on the eve of war. The breaking of Enigma in its wartime variations required a major new intelligence recruitment. In 1937, the Chief of the Secret Service, Admiral Sir Hugh ‘Quex’ Sinclair, told Denniston that he was now ‘convinced of the inevitability of war’ and gave ‘instructions for the earmarking of the right type of recruit immediately on the outbreak of war’ – chief among them what were quaintly called ‘men of the professor type’. The most active recruiters of ‘professor types’ were two Fellows of King’s College, Cambridge, who had served in Room 40, the main First World War Sigint agency: Frank Adcock (later knighted), Professor of Ancient History, and the historian Frank Birch, who left Cambridge for the stage in the 1930s. Both inevitably looked for recruits in the places they knew best: Cambridge colleges in general and King’s in particular. A total of twelve King’s dons served at Bletchley during the Second World War. By great good fortune the King’s Fellowship included Alan Turing, still only twenty-seven at the outbreak of war, one of the very few academics anywhere in the world to have carried out research into both computing and cryptography. Turing’s pioneering paper, ‘Computable Numbers’, now recognized as one of the key texts in the early history of modern computer science, was published early in 1937, though it attracted little interest at the time. Three months before its publication Turing, then at Princeton, wrote to tell his mother that he had also made a major breakthrough in the construction of codes. In view of his later exploits at Bletchley Park, Turing’s letter now seems wonderfully ironic:
I expect I could sell [the codes] to HM Government for quite a substantial sum, but am rather doubtful about the morality of such things. What do you think?
Turing went on to become the chief inventor of the ‘bombes’ used to break Enigma.
The search for ‘professor types’, of whom Turing was probably the most remarkable, even in a highly distinguished field, followed two important precedents established during the selection of British codebreakers in the First World War: the recruitment of unusually youthful talent and of original minds who would have been regarded as too eccentric for employment by most official bureaucracies. (The two categories, of course, overlapped.) Two of Britain’s leading codebreakers in the two world wars, Dillwyn ‘Dilly’ Knox and Alan Turing, both Fellows of King’s, were also among the most eccentric. Knox, a classicist, did some of his best work for Room 40 lying in a bath in Room 53 at the Admiralty Old Building on Whitehall, claiming that codes were most easily cracked in an atmosphere of soap and steam. Frank Birch wrote affectionately of Knox in his classified satirical history of Room 40, Alice in ID25:
The sailor in Room 53
has never, it’s true, been to sea
but though not in a boat
he has served afloat –
in a bath in the Admiralty.
Knox’s bathtime cryptanalysis continued during his time at Bletchley Park, once causing fellow lodgers at his billet, when he failed to respond to shouted appeals through the bathroom door, to break down the door for fear that he might have passed out and drowned in the bath.
Turing’s eccentricities make such engaging anecdotes that they are sometimes exaggerated, but there can be no doubt about their reality. His ability from a very early age to disappear into a world of his own is wonderfully captured by a drawing of him at prep school by Turing’s mother, which she presented to the school matron. The drawing, entitled ‘Hockey or Watching the Daisies Grow’, shows the ten-year-old Turing, oblivious of the vigorous game of hockey taking place around him, bending over in the middle of the pitch to inspect a clump of daisies. At Bletchley Park he chained his coffee mug to a radiator to prevent theft, sometimes cycled to work wearing a gas mask to guard against pollen, and converted his life savings into silver ingots which he buried in two locations in nearby woods. Sadly, he failed to find the ingots when the war was over. The informality and absence of rigid hierarchy at Bletchley Park enabled it to exploit the talents of unconventional and eccentric personalities who would have found it difficult to conform to military discipline or civil service routine.
Most of the dons and other professionals recruited by Room 40 had been young. The ‘professor types’ selected by Bletchley Park were, on average, younger still. In the summer of 1939, Alastair Denniston wrote to the heads of about ten Cambridge and Oxford colleges, asking for the names of able undergraduates who could be interviewed for unspecified secret war work. Among the twenty or so recruited during the first round of interviews (repeated on a number of later occasions during the war) was the twenty-year-old Harry Hinsley, who was about to begin his third year as an undergraduate historian at St John’s College, Cambridge. After Pearl Harbor, when Bletchley Park needed more cryptanalysts and linguists to take newly devised crash courses in the Japanese language, the recruitment included sixth-formers as well as undergraduates – among them Alan Stripp, recruited after winning a classics scholarship to Trinity College, Cambridge, who later co-edited with Hinsley a volume of memoirs on Bletchley Park. During a visit to Bletchley, Churchill is said to have remarked ironically to Denniston, as he surveyed the unusually youthful staff, ‘I told you to leave no stone unturned to get staff, but I had no idea you had taken me literally.’
Recruitment to Bletchley Park broke with one important but misguided precedent established during the First World War. Room 40 had made no attempt to recruit professional mathematicians, whose supposedly introverted personalities were thought to be too far removed even from the realities of daily life for them to engage with the horrendous problems posed by the First World War. Though a prejudice normally associated with arts graduates, this jaundiced view of mathematicians appears to have been shared by the Director of Naval Education, Sir Alfred Ewing, a former Fellow of King’s and Professor of Engineering at Cambridge, who seems to have been chiefly responsible for the recruitment from King’s (where his son-in-law remained a Fellow) of Adcock, Birch and Knox. Despite his own mathematical training, Ewing evidently considered the experience of classicists, historians and linguists in making sense of difficult and complex texts a more relevant skill for cryptanalysis than mathematical expertise. Similar prejudices continued to influence the recruitment of British cryptanalysts between the wars.
Polish military intelligence realized at the end of the 1920s that the attempt to break Enigma would require the recruitment of professional mathematicians (one of whom, Marian Rejewski, was to make the first major breakthrough in the attack on it). In the summer of 1938, Denniston finally reached a similar conclusion and began including a limited number of mathematicians among the ‘professor types’ who were being earmarked for Bletchley Park. Initially, however, the mathematicians were treated with considerable caution and some suspicion. The first mathematics graduate recruited by GC&CS, Peter Twinn of Brasenose College, Oxford, was told after he began work early in 1939, that ‘there had been some doubts about the wisdom of recruiting a mathematician as they were regarded as strange fellows, notoriously unpractical’. Twinn owed his recruitment, at least in part, to his postgraduate work in physics. Physicists, he was told, ‘might be expected to have at least some appreciation of the real world’ – unlike, it was believed, most mathematicians.
Though the first wave of ‘professor types’ to arrive at Bletchley Park at the outbreak of war consisted chiefly of linguists, classicists and historians, it also included two brilliant Cambridge mathematicians: Turing from King’s and Gordon Welchman from Sidney Sussex College, who may originally have been earmarked because his mathematical brilliance was combined with skill at chess. According to the Cambridge Professor of Italian, E. R. ‘Vinca’ Vincent – probably the first ‘professor type’ to be selected – ‘Someone had had the excellent idea that of all people who might be good at an art that needs the patient consideration of endless permutations, chess players fitted the bill.’ Among other chess experts to arrive at Bletchley Park in the early months of the war were Hugh Alexander and Stuart Milner-Barry. Turing, Welchman, Alexander and Milner-Barry were jointly to sign the celebrated Trafalgar Day memorandum in 1941, which Churchill minuted, ‘Action This Day’. Whatever the original reasons for their recruitment, the first professional mathematicians at Bletchley Park made themselves indispensable so quickly that the recruiting drive was rapidly extended to mathematicians without a reputation as chess players.
Though GC&CS operated on a very much larger scale after its wartime move to Bletchley Park than it had done between the wars, at least one aspect of its original organization remained both of crucial importance and considerably ahead of its time. Denniston considered the ‘official jealousy’ which had prevented any collaboration between naval and military cryptanalysts from October 1914 to the spring of 1917 ‘the most regrettable fact’ in the history of British wartime Sigint. The establishment of GC&CS in 1919 was intended to avoid any repetition of such interdepartmental feuding. Within a few years of its foundation the new agency achieved the successful co-ordination of diplomatic and service cryptanalysis under overall Foreign Office control, though for most of the interwar years diplomatic decrypts yielded much more valuable intelligence than service traffic. That co-ordination, equalled by no other major Sigint agency abroad, was one of the secrets of Bletchley Park’s success.
For much of the 1930s the bitter rivalry between US naval and military Sigint agencies closely resembled that between their British counterparts during the First World War. Each sought to crack independently the same diplomatic codes and ciphers in order, according to a declassified official history, to ‘gain credit for itself as the agency by which the information obtained was made available to the Government’. Though there was limited interservice collaboration at the end of the decade, the rivalry resumed after the breaking of the Japanese Purple diplomatic cipher by military cryptanalysts in September 1940, as naval codebreakers sought to prevent the Army from monopolizing Magic (Japanese diplomatic decrypts). After lengthy negotiations, an absurd bureaucratic compromise was agreed, allowing the military Signal Intelligence Service (SIS) to produce Magic on even dates, and its naval counterpart, OP-20-G, to do so on odd dates. This bizarre arrangement continued to cause confusion until the very eve of Pearl Harbor. On the morning of Saturday 6 December, a naval listening post near Seattle successfully intercepted thirteen parts of a fourteen-part message from Tokyo to the Japanese embassy in Washington, rejecting US terms for a resolution of the crisis and making clear that there was no longer any prospect of a peaceful settlement. (The fourteenth part was intercepted on the following day.) This critically important intercept was forwarded by teleprinter to the Navy Department in Washington. But since 6 December was an even date, the Navy Department was obliged to forward the message to the military SIS for decryption shortly after midday. SIS, however, found itself in a deeply embarrassing position since its civilian translators and other staff, as usual on a Saturday, had left at midday and there was no provision for overtime. Doubtless to its immense chagrin, SIS was thus forced to return the intercept to the Navy. While OP-20-G began the decryption, SIS spent the afternoon gaining permission for its first Saturday evening civilian shift. By the time the shift started, however, it was too late for SIS to reclaim the partly decrypted intercept from OP-20-G. And so, for the first time, on the eve of Pearl Harbor, the rival agencies produced Magic together. SIS was able to decrypt two of the thirteen parts of the intercepted Japanese message, though the typing was done by the Navy. The Sigint confusion in Washington, at one of the most critical moments in American history, highlights the immense importance of the successful resolution of interservice rivalry by GC&CS two decades earlier.
Equally essential to Bletchley Park’s success was Churchill’s passion for Sigint. By a remarkable – and fortunate – coincidence, Churchill became war leader shortly after the first Enigma decrypts, one of the most valuable intelligence sources in British history, began to come onstream. Churchill’s passion for Ultra was equalled only by his determination to put it to good use. On the tenth anniversary in 1924 of the founding of Room 40, he had described Sigint as more important to the making of foreign and defence policy than ‘any other source of knowledge at the disposal of the state’. He was also well aware that, despite some successes during the First World War, the advantage gained by breaking German codes had sometimes been wasted. The indecisive battle of Jutland in 1916, the greatest naval battle of the war, might well have ended in a decisive British victory if the Sigint provided by Room 40 had been properly used by the Admiralty. Churchill’s own use of Ultra during the Second World War was, of course, far from infallible. The exaggerated sense of Rommel’s weakness in North Africa which he derived from his over-optimistic interpretation of Enigma decrypts, for example, made him too quick to urge both Wavell and Auchinleck to go on the offensive.
Even when due account is taken of Churchill’s limitations, however, he still remains head and shoulders above any other contemporary war leader or any previous British statesman in his grasp of Sigint’s value. That grasp depended on an experience of Sigint which went back to the founding of Room 40 early in the First World War and on his ability to learn from his mistakes in the handling of it. Had Churchill come to power in May 1940 without previous experience of Sigint, Bletchley Park might well have found his untutored enthusiasm for Ultra a dubious asset.
Great war leader though he was in most other respects, President Franklin D. Roosevelt was simply not in Churchill’s class when it came to Sigint. Despite a general awareness of the importance of wartime intelligence and a particular fascination with espionage, dating back to his experience of naval intelligence in the First World War, Roosevelt failed to grasp the importance of Sigint. Though Magic provided by far the best guide to Japanese policy during the year before Pearl Harbor, he showed only a limited interest in it. As well as sanctioning the absurd odd-even date division of labour between naval and military cryptanalysts, he also agreed to a further bizarre arrangement by which his naval and military aides took turns in supplying him with Magic in alternate months. This arrangement led to predictable confusion, including the suspension of the Magic supply in July 1941, after FDR’s military aide breached Sigint security by absentmindedly leaving Japanese decrypts in his wastepaper basket. Not until November did the President finally lose patience and insist that Magic henceforth be communicated to him exclusively through his naval aide, Captain John R. Beardall. When shown Japanese decrypts, Roosevelt very rarely commented on them. Not until three days before Pearl Harbor did he discuss with Beardall the significance of any of the Magic revelations.
Churchill would never have tolerated the confusion allowed by Roosevelt in both the production and the distribution of Magic. He also showed far greater appreciation both of his cryptanalysts and the intelligence which they produced. Captain Malcolm Kennedy, one of the leading Japanese experts at Bletchley Park, wrote in his diary on 6 December 1941:
… The All Highest (… Churchill) is all over himself at the moment for latest information and indications re Japan’s intentions and rings up at all hours of the day and night, except for the 4 hours in each 24 (2 to 6 a.m.) when he sleeps. For a man of his age, he has the most amazing vitality.
It would never have occurred to Roosevelt to ring up his cryptanalysts for the latest news. (Had he done so on 6 December, he would have discovered the confusion in the decryption of the fourteen-part Japanese telegram caused by the odd-even day arrangement.) Churchill also showed far greater determination than Roosevelt to ensure that his cryptanalysts had adequate resources. The American intelligence failure to provide advance warning of the Japanese attack on Pearl Harbor was due primarily to the difficulties in reading the latest variant of the main Japanese naval code, JN-25B. Though Magic contained no clear indication of plans for the surprise attack, undecrypted naval messages did. ‘If the Japanese navy messages had enjoyed a higher priority and [had been] assigned more analytic resources,’ writes the official historian of the NSA (the current US Sigint agency), Frederick Parker, ‘could the U. S. Navy have predicted the Japanese attack on Pearl Harbor? Most emphatically yes!’ JN-25B was not read to any great extent before Pearl Harbor because only a total of between two and five cryptanalysts had ever been assigned to work on it. The success in breaking Japanese naval codes, when the number of cryptanalysts was increased after Pearl Harbor, was a crucial element in the US victory at Midway only six months later.
In the months before Pearl Harbor, when OP-20-G lacked the resources required to read JN-25B more fully, it did not occur to American naval cryptanalysts to appeal directly to Roosevelt. At exactly the same time, faced with a less critical though still serious shortage of resources, Bletchley Park’s leading cryptanalysts appealed directly to Churchill. The most junior of them, Stuart Milner-Barry, delivered the message personally to Number 10. Churchill’s response was immediate: ‘ACTION THIS DAY. Make sure they have all they want on extreme priority and report to me that this has been done.’
2
THE GOVERNMENT CODE AND CYPHER SCHOOL AND THE FIRST COLD WAR
MICHAEL SMITH
Introduction
Our view of espionage is now so dominated by the period known as the Cold War, that it is easy to forget that between the First and Second World Wars, Britain and the Soviet Union fought a first Cold War every bit as bitter as the second. The predecessors of the KGB regarded Britain as ‘the main adversary’ and there were widespread attempts to collect intelligence, to subvert British society, and to recruit agents within the British establishment, of whom the members of the Cambridge spy ring were only the most prominent. The following chapter traces the early beginnings of GC&CS and examines the part played by the British codebreakers in this first Cold War. It also dismantles the myth that once the Germans turned on the Russians - in June 1941 - the British stopped collecting intelligence on their newfound Soviet allies. Although their armies were united in the ‘hot war’ against Germany, the intelligence services on bothsides would very soon be positioning themselves to fight the new Cold War that would follow the victory over the Nazis.
MS
Britain’s codebreakers enjoyed a very successful First World War. Perhaps the best known of their achievements was the breaking, by the Royal Navy’s Room 40, of the Zimmermann Telegram, which brought the United States into the war. But even before Room 40 was created, on the orders of the then First Lord of the Admiralty, Winston Churchill, the Army’s MI1b had achieved considerable success against German military codes and ciphers.
The Army and Navy codebreaking units rarely spoke to each other, engaging in a turf war apparently fuelled by the Army’s resentment of the greater influence of the upstart in the Admiralty. Alastair Denniston, who for much of the war led Room 40, or NID25, as it was more correctly known, later bemoaned ‘the loss of efficiency to both departments caused originally by mere official jealousy’. The two departments finally began to exchange results in 1917, but there remained little love lost and the situation came to a head a year after the Armistice, when the question of whether or not there should be a peacetime codebreaking organization was under consideration.
Although there were inevitably some within government who were keen to axe the codebreakers as part of a peace dividend, there were many more who were just as eager to continue to receive the intelligence they were providing. It was decided to amalgamate the two organizations and a conference was held at the Admiralty in August 1919 to consider who should be in charge of the new body. The War Office wanted their man. Major Malcolm Hay, the head of MI1b, while the Navy was equally determined that Denniston was the worthier candidate.
But Hay appears to have overplayed his hand, insisting he was not prepared to work under Denniston, while the latter expressed a willingness to do whatever was asked of him. The generals were embarrassed by Hay’s attitude. It was not for junior officers to decide who they were or were not prepared to serve under. Denniston was subsequently given charge of what was to be known as the Government Code and Cypher School (GC&CS), with a staff of just over fifty employees, of whom only a half were codebreakers. ‘The public function was “to advise as to the security of codes and cyphers used by all Government departments and to assist in their provision”,’ Denniston later recalled. ‘The secret directive was “to study the methods of cypher communications used by foreign powers”.’
GC&CS came under the control of the Director of Naval Intelligence, Admiral Hugh ‘Quex’ Sinclair, a noted bon viveur who installed the School in London’s fashionable Strand, close to the Savoy Grill, his favourite restaurant. The material it dealt with was almost entirely diplomatic traffic. Its main target countries were America, France, Japan and Russia, with the last providing what Denniston said was ‘the only real operational intelligence’.
‘The Revolutionary Government in 1919 had no codes and did not risk using the Tsarist codes, which they must have inherited,’ Denniston said. ‘They began with simple transposition of plain Russian and gradually developed systems of increasing difficulty.’ One of the reasons that the Bolsheviks were unwilling to use the old Tsarist codes was the presence among the British codebreakers of the man responsible for devising a number of them. Ernst Fetterlein had once been the Tsar’s leading code-breaker, solving not just German and Austrian codes but also those of the British.
‘Fetterlein was a devotee of his art,’ one of his former colleagues in the Russian Cabinet Noir recalled. ‘I was told that once, when he was sent to London with dispatches, he sat morosely through breakfast until suddenly a complete change took place. He beamed, began to laugh and jest, and when one of the embassy officials asked him what the matter was, confessed that he had been worried by an indecipherable word which occurred in one of the English telegrams he had deciphered. Someone had in conversation mentioned the name of a small English castle to which the King had gone to shoot and this was the word in the telegrams which had bothered him.’ He sported a large ruby ring given to him by Tsar Nicholas in gratitude for his achievements, which included deciphering a message that led to the sinking of a number of German ships in the Baltic in 1914. This had a valuable spin-off for Fetterlein’s future employers. The Russians recovered a naval codebook from the light cruiser the Magdeburg, which they passed on to the British.
Fetterlein fled from Russia during the October Revolution on board a Swedish ship. He and his wife narrowly evaded a search of the ship by the Russians, one of his new colleagues recalled him saying. ‘As the top cryptographer in Russia he held the rank of admiral and his stories of the day the revolution occurred, when workmen stripped him of many decorations and bullets narrowly missed him, were exciting. It is said that the French and the British organisation were anxious to get him and Fetterlein simply sat there and said: “Well gentlemen, who will pay me the most?”’
The British evidently offered the most money. Fetterlein was recruited by Room 40 in June 1918, working on Bolshevik, Georgian and Austrian codes. ‘Fetty, as we addressed him, would arrive precisely at 9.30 and read his Times until 10 when he would adjust a pair of thick-lensed glasses and look to us expecting work to be given to him. He was a brilliant cryptographer. On book cipher and anything where insight was vital he was quite the best. He was a fine linguist and he would usually get an answer no matter the language.’
Fetterlein and his team, who included two female refugees from Russia and the occasional British Consul thrown out by the Bolsheviks, were easily able to keep on top of the relatively simple Bolshevik ciphers. This allowed them to ensure that the government of David Lloyd George was fully informed of the machinations of various elements of the Russian Trade Delegation, led by the Bolshevik Commissar for Foreign Trade, Leonid Krasin, which arrived in London in May 1920.
The messages decrypted by GC&CS were known as BJs because they were circulated in blue-jacketed files, as opposed to the red files used for reports from the Secret Intelligence Service (SIS), now better known as MI6. The Russian BJs showed Lenin telling Krasin that he must be tough with the British. ‘That swine Lloyd George has no scruples or shame in the way he deceives,’ said the Soviet leader. ‘Don’t believe a word he says and gull him three times as much.’ Lev Kamenev, the head of the Moscow Communist Party, was sent to London to take charge of the delegation. Very soon the decrypts showed that he was actively involved in the setting up of ‘Councils of Action’ across Britain, with the intention of using them, like the Russian Soviets, to prepare for a communist revolution in Britain. They also disclosed that the Russians were pouring money into the London-based Daily Herald newspaper.
To many of those in authority, it appeared that Britain was perilously close to its own communist insurrection. Field Marshal Sir Henry Wilson, the Chief of the Imperial General Staff, wrote a furious memorandum to Lloyd George. The telegrams showed ‘beyond all possibility of doubt … that Kamenev and Krasin, while enjoying the hospitality of England, are engaged, with the Soviet Government, in a plot to create red revolution and ruin this country’. He received support from Admiral Sinclair, who surprisingly urged the Government to publish the decrypted telegrams. ‘Even if the publication of the telegrams was to result in not another message being decoded, then the present situation would fully justify it,’ claimed Sinclair.
Lloyd George then sanctioned the publication of eight of the telegrams as long as the newspapers claimed to have obtained them from ‘a neutral country’. But The Times ignored the official requests to keep the true source secret, starting its report with the words: ‘The following telegrams have been intercepted by the British Government.’ The Prime Minister called in Kamenev, who was due to return to Russia for consultations and told him there was ‘irrefutable evidence’ that he had committed ‘a gross breach of faith’. He would not be allowed back into the country.
Despite the Times report, and further press leaks after Kamenev’s departure, the Russians did not change their ciphers. There was no doubt that they were aware of what had happened. Krasin told Maxim Litvinov, the Bolshevik Deputy Commissioner for Foreign Affairs, that the British ‘had complete knowledge of all your ciphered telegrams … which had strengthened the suspicion that Kamenev is the teacher of revolutionary Marxism and was sent here with the express purpose of inspiring, organizing and subsidizing English Soviets’.
But the Russian ciphers were still not changed until three months later, when Mikhail Frunze, Commander-in-Chief of the Bolshevik forces fighting the White Russians in the Crimea, reported that ‘absolutely all our ciphers are being deciphered by the enemy in consequence of their simplicity’. He singled out the British as one of the main perpetrators. ‘All our enemies, particularly England, have all this time been entirely in the know about our internal military operational and diplomatic work,’ he added. A week later, the trade delegation in London was told to send correspondence by courier until they received new ciphers. They arrived in January 1921 and by April, Fetterlein had broken them.
The main source of the coded messages coming into GC&CS was the international cable companies. Under a section added to the 1920 Official Secrets Act, they were obliged to hand over any cables passing through the United Kingdom – a requirement that was quite openly put down to the ‘general state of world unrest’ created by communist attempts to replicate the October Revolution across Europe. But many of the messages emanating from Moscow were intercepted by Royal Naval intercept sites – based at Pembroke and Scarborough – and Army sites at Chatham, Baghdad and Constantinople. Although GC&CS remained under Admiralty control, the vast bulk of the messages it decrypted were now diplomatic rather than military or naval and in 1922, Lord Curzon, the Foreign Secretary, decided that the Foreign Office should take charge of the codebreakers. One senior member of staff attributed this to a conversation with the French ambassador during which the Foreign Secretary ‘expressed certain views which did not coincide with the views of his colleagues in the cabinet’. These were duly passed back to Paris, decrypted by GC&CS and circulated among Curzon’s cabinet colleagues. The codebreakers were moved from their Strand headquarters to 178 Queen’s Gate and a year later again put under the control of Admiral Sinclair, who was now the Chief of MI6.
Despite his interest in the codebreakers’ intelligence product, Curzon showed little regard for its security. When further evidence of the Russian attempts to subvert Britain and its empire emerged in 1923, he used the deciphered telegrams to draft a protest note to the Soviet Government – the so-called Curzon ultimatum – which not only quoted the telegrams verbatim but made absolutely clear that they were intercepts, most of them passing between Moscow and its envoy in Kabul. These were almost certainly intercepted, and probably deciphered, in India where there was a well-established signals intelligence operation.
One of the leading cryptographers in India at the time was Captain John Tiltman, who was undoubtedly one of the best codebreakers in Britain, if not the world. He had been offered a place at Oxford at the age of thirteen but had been unable to accept. He subsequently served with the King’s Own Scottish Borderers in France during the First World War, where he won the Military Cross, and spent a year with GC&CS before being posted to the Indian Army headquarters at Simla in 1921. There was already a military intercept site at Pishin on the Baluchistan-Afghan border and Tiltman’s arrival coincided with the opening of another intercept station at Cherat, on the North West Frontier.
Tiltman later recalled that he was part of a small section of no more than five people based at Simla. It not only deciphered the messages, but also garnered intelligence from the locations of the transmitters – which were determined by direction finding – from the way they operated, and from the routine communications, a process still known today as traffic analysis. ‘We were employed almost entirely on one task, to read as currently as possible the Russian diplomatic cipher traffic between Moscow, Kabul in Afghanistan and Tashkent in Turkestan,’ he said. ‘From about 1925 onwards, I found myself very frequently involved in all aspects of the work – directing the interception and encouraging the operators at our intercept stations on the North West Frontier of India, doing all the rudimentary traffic analysis that was necessary, diagnosing the cipher systems when the frequent changes occurred, stripping the long additive keys, recovering the codebooks, translating the messages and arguing their significance with the Intelligence Branch of the General Staff. I realize that I was exceptionally lucky to have this opportunity and that very few others have had the chance of acquiring this kind of general working experience. Between 1921 and 1924, I paid three visits to the corresponding unit in Baghdad and on several occasions, sitting amongst operators in the set-room of the Baghdad intercept station, worked directly on the red forms fresh off the sets, to the benefit not only of my own experience but also to the morale of the operators.’
The Indian signals intelligence operation, which was regarded as part of Sinclair’s overall organization, took any Russian traffic it could, including the communications of the OGPU, forerunner of the KGB. It achieved ‘very considerable cryptographic success’, according to one military official. A Wireless Experimental Station was opened at Abbottabad on the North West Frontier with a further intercept site at Quetta. Meanwhile, the site in Constantinople was withdrawn to Sarafand, near Jaffa, in Palestine, as No. 1 section of 2 Wireless Company, with Baghdad forming No. 2 section. Like the Indian operation, Sarafand had its own cryptographers, producing intelligence for the British Middle East Command. It also sent raw Russian traffic back to London where it was passed on to GC&CS, considerably increasing the amount of Russian traffic available to Fetterlein and his assistants.
The increased amount of traffic coincided with yet another change in the Soviet ciphers, leading to calls for more Russian experts. One of those recruited as a result was J. E. S. ‘Josh’ Cooper, who was to become another leading light at Bletchley Park. He heard of the openings at GC&CS through a friend, the novelist Charles Morgan.
I joined as a Junior Assistant in October 1925. Like many other recruits, I had heard of the job through a personal introduction – advertisement of posts was, at that time, unthinkable. I was one year down from University of London, King’s College, with a first in Russian and had nothing better to do than teach at a preparatory school at Margate. My father was bewailing this at tea with the Morgans one day, and one of Charles’s sisters said she had a friend who worked at a place in Queen’s Gate where Russian linguists were wanted.
Cooper already knew Fetterlein, having been introduced to him by one of the teaching staff at King’s College.
His experience and reputation were both great, and I was fortunate to find myself assigned to work with him on Soviet diplomatic, which at that time consisted of book ciphers, mostly one part, reciphered with a 1,000-group additive key. He took very little notice of me and left it to an army officer who had been attached to GC&CS, Capt. [A. C.] Stuart Smith, to explain the problem and set me to recover some Russian additive key. Traffic was scanty and it was hard to get adequate depth. Also the book I was working with had been solved in India by Tiltman and Col. Jeffrey and nobody had worked on it at home. It took me some time to realize that almost every group had two meanings. After about six weeks’ work, during which I rubbed holes in the paper with endless corrections, at last I read my first message which was from Moscow to the Soviet representative in Washington and was concerned with repudiation of debts by American states.
Despite Cooper’s problems with the cipher he was put to work on, the amount of Soviet messages continued to increase with the opening of a new Royal Navy intercept site at Flowerdown, near Winchester, an army site at Chatham, and an RAF site at Waddington, in Lincolnshire. Sinclair moved both the code-breakers and his MI6 staff to a new joint headquarters at 54 Broadway, close to Whitehall, in 1925. He also added to the intercept facilities by co-opting the resources of a small Metropolitan Police intercept operation, which was run by Harold Kenworthy, an employee of Marconi who was on indefinite loan to the police. It operated out of the attic at Scotland Yard, employing a number of ex-naval telegraphists to intercept illicit radio stations.
The Metropolitan Police unit had first shown its capabilities during the 1926 General Strike. Although the strike broke out largely for socioeconomic reasons, the BJs had shown the Soviet Government keen to provoke industrial action to the extent of subsidizing the striking miners to the tune of £2 million. It was scarcely surprising therefore that when, on the first day of the General Strike, the Metropolitan Police operators intercepted an unusual wireless transmission using apparently false callsigns and emanating from somewhere in London, there were suspicions of Russian foul play. Kenworthy informed the assistant commissioner in charge of the Special Branch who in turn contacted Admiral Sinclair. The MI6 Chief sent over the GC&CS radio expert Leslie Lambert, better known as the BBC ‘wireless personality’ A. J. Alan, and together they constructed a miniature direction-finding device small enough to fit into a Gladstone bag, Kenworthy recalled.
The portable set was put to good use. Influence by Assistant Commissioner and SIS [MI6] made it possible to get access to roofs of buildings in the vicinity of the suspected source of signal which had been roughly located by taking a completely empty van and sitting on the floor with the Gladstone bag. It was gratifying that the work put in was finally rewarded by actually ‘walking in’ from the roof tops into the top of a building housing the transmitter whilst the operator was using it. The result was an anti-climax as the transmitter had been set up by the Daily Mail, who thinking that Post and Telegraph personnel would be joining the strike at any moment, decided to try and be ready for a ‘coup’. The call sign AHA was derived from [the newspaper’s proprietor] Alfred Harmsworth. As a matter of high policy nothing was ever published about this exploit.
The illicit radio transmitter may not have been run by the Russians, but the General Strike and Moscow’s attempts to inspire revolution in China and to take control of Afghanistan – and thereby threaten India – increased the general feeling within the Conservative-led establishment that the Bolsheviks were determined to subvert Britain and its Empire.
Government ministers were also influenced by MI5 and Special Branch reports of Soviet espionage centred on ‘the firm’, a cover name for the All-Russian Co-operative Society (ARCOS) based in Moorgate, ostensibly set up to facilitate trade between Britain and Russia. None were anywhere near as successful as the later Cambridge spy ring, but their attempts to obtain military and naval intelligence outraged those like the intensely anti-Bolshevik Home Secretary Sir William Joynson-Hicks, who put pressure on the then Foreign Secretary Sir Austen Chamberlain to back action against Russia. Throughout 1926, Chamberlain continued to defend his policy of pragmatic dealing with Moscow rather than lose the new trade links. But by 19 January 1927, he accepted that there was a need ‘to review in Cabinet our relations with Russia’, asking the President of the Board of Trade what Britain’s ‘actual trade interests’ amounted to, and for some sense of ‘the sentiment of traders’ about them. Five days later, he drafted a protest note to the Russians. He suspected that it would not satisfy Joynson-Hicks, or the other hardliners like Winston Churchill, now Chancellor of the Exchequer, and he was right. But it was the start of a process that would soon lead to a complete diplomatic break with Moscow.
