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Ultra Ultra Secrets

British Intelligence in the Second World War: Its Influence on Strategy and Operations

by F.H. Hinsley, by E.E. Thomas, by C.F.G. Ransom, by R.C. Knight
Cambridge University Press, Vol. II: 850 pp., $39.50

Intelligence was the British success story of the Second World War. The Russian army broke the power of the Wehrmacht, and American industry provided the material superiority that allowed Britain to survive and triumph. The British war record was a mixed one, but in intelligence its victory over the Germans was indisputable. Stories about espionage and counterespionage, clandestine operations and prisoner-of-war escapes flooded the market after the war. The Wooden Horse, The White Rabbit, and M.R.D. Foot’s semiofficial SOE in France were all best sellers. But in 1974, the publication of The Ultra Secret by a former air intelligence officer, F.W. Winterbotham, opened a new chapter in the history of the European war. 1 Winterbotham, defying a strictly enforced government ban, revealed that through intercepting and decoding radio signals, the British had been able to read the strategic and tactical information being relayed at every level of the three German armed forces and many domestic messages as well. The Germans knew nothing of this. They thought the codes and ciphers for their “Enigma” machine were impregnable. The story of the British triumph became the best-kept secret of World War II.

Winterbotham’s account provoked heated comment. Claims and counterclaims about distortions in The Ultra Secret appeared in the letter columns of The Times. More revelations followed about Enigma keys and navigational beams, ciphers and codes. This was not the world inhabited by Smiley’s friends. The government did not prosecute. Instead, the Cabinet Office agreed to commission and then publish an official history of wartime intelligence, the first and, thus far, the only government to do so. They turned to F.H. Hinsley, a diplomatic historian and professor of international relations at Cambridge University and currently its vice-chancellor.

Hinsley was doubly qualified for the job: as a young St. John’s undergraduate he had been recruited for the naval section at Bletchley Park, a country house about fifty miles from London which became the wartime center of Britain’s cryptographic work. Hinsley and his colleagues were given free access to all intelligence archives, even those that could not be cited and might never come into the public domain. The authors made their way through the archives and the bureaucratic jungles at home and abroad. Their first volume appeared in 1979, the next two years later, and there is a third still to come. No one concerned with the Second World War can ignore these books, for they show the European struggle in a new light.

Intercepting and deciphering radio signals was an old intelligence art. The British had created small cryptographic departments (the Admiralty’s Room 40) during the First World War but had failed to actively pursue these efforts in the interwar period. The Germans, on the other hand, had marketed and named a Dutch-invented ciphering machine in the early 1920s. The Enigma machine was bought first by the German navy and then by the other German armed forces and security services. Now found only in intelligence museums, Enigma was an electrically powered mechanical box, resembling a typewriter, in which sets of drums or wheels marked with numbers and letters could be so manipulated as to re-encode an original cipher.

Machine encipherment set decoding problems of an entirely different kind from the ones traditionally handled by intelligence bureaus. Fortunately for the Allies, the Polish secret service had secured an adapted version of the Enigma machine and a small group of Polish mathematicians had unraveled its workings and devised ways to read its daily settings. Between 1933 and 1938, they secretly read a large amount of German Enigma traffic. Then a series of German advances defeated the Polish cryptographers, and after mid-December 1938 all efforts at decoding failed. Realizing that war was imminent, the Poles met with French and British representatives and presented each with an Enigma built in Poland and technical drawings of a machine (“Bombe”) devised for finding Enigma keys through the rapid and automatic testing of many thousands of possible combinations. A few Polish code breakers joined a French team working in Paris. Fleeing in 1942, they were captured by the Gestapo but did not reveal their secret. Aided by these early Polish and French efforts, the British started on their own crash program just before the war broke out.

Only in 1939, during the Munich crisis, was the small interwar Government Code and Cypher School moved to Bletchley Park. A hastily assembled team of some twenty “men of the professor type,” as they were called, mostly in their twenties or early thirties, were brought from Cambridge and Oxford to work on the Enigma problem. The main recruiters were two historians from King’s College, Cambridge, Frank Adcock and Frank Birch, both of whom had served as naval cryptographers during the First World War.2 The first group of recruits included linguists, historians, and classicists, but also, because of the new problems posed by Enigma, two or three mathematicians, among them Alan Turing, reputed the most brilliant of the Bletchley Park code breakers. The dons were followed by their students. King’s College alone contributed twelve cryptologists, more than any other single institution. These young academics, about sixty at the start of the war, augmented with recruits from other rapidly expanded intelligence departments, were to carry off the most important intelligence coup of the war. Their first success came in May 1940 with the cracking of the German air force Enigma key.

Intelligence gathered from the breaking of the “most highly secret” Enigma traffic from Germany was known as Ultra. This was handled by the small elite group of cryptographers and intelligence men and circulated only to a very restricted circle of users including Winston Churchill. In addition, and involving far more people at Bletchley Park, the “Y” service dealt primarily with wireless traffic in low- and medium-grade codes and ciphers which, because of their bulk and frequency, yielded a wide variety of tactical information bearing on current military operations. The “Y” service distributed this lower-grade intelligence to the military commands. Thanks to these sources, British intelligence could often literally read the German mind. It could do so reliably, at high speed, and without involving vulnerable agents. “Sigint”—all forms of intelligence from wireless signals—and especially Ultra were indestructible weapons.

The degree of British success in decoding varied considerably. Each German service had a variety of keys. By the end of the war, some twenty naval and two hundred non-naval keys had been identified. The easiest to read were the German air force keys; the naval keys were more difficult and the army’s the most recalcitrant of all. The Gestapo Enigma key was never broken; the underlying reason, I gather, was the scarcity of messages to be worked on. However, in the valuable and fascinating appendixes to Volume II, Hinsley notes that the British were reading the Enigma traffic of the SS and the German police. From the spring of 1942 until February 1943, they deciphered lists of prisoners at Dachau, Buchenwald, and Auschwitz; yet the “terrible secret” of Auschwitz was not publicly known until 1944. These lists recorded the number of inmates, new arrivals, and “departures by any means,” i.e., deaths. So far we have had no public account of what happened to this information, who knew about it, and why it took so long for the news to spread.

The interception, decoding, analysis, interpretation, and distribution of signal intelligence involved a vast administrative effort. In a series of dense but important chapters, Professor Hinsley discusses the organization of the intelligence community and the tangled story behind the development of Bletchley Park. The intelligence services before World War II were multiple, small, and competing. Among others, there were the intelligence divisions of the Admiralty, the War Office, and the Air Ministry. The Special or Secret Intelligence Service (SIS or MI6), which was responsible for espionage, and the Government Code and Cypher School, were both under the control of the Foreign Office. MI5 was responsible for counter-espionage. As in the United States, all had been starved of men and funds during the interwar period. The Foreign Office took little interest in the SIS, which attracted few men, and those were considered of doubtful quality. In fact, the SIS generally avoided university types lest they be tarred with Bolshevism, leaving that fertile field to their Soviet rivals. Anthony Blunt, Guy Burgess, Donald Maclean, and Leo Long were recruited from Cambridge as potential Soviet spies during the 1930s.

If Bletchley Park were to work effectively, the three service departments and the Foreign Office had to be convinced that cryptography and intelligence should be undertaken on an interservice basis. All the activities at Bletchley Park were placed under the control of “C,” Col. Stewart Menzies, the not very intelligent but highly respected head of the SIS. There evolved by 1941 an effective Joint Intelligence Committee and a Joint Intelligence Staff.

Those familiar with the interdepartmental wars fought in Washington (where visiting British cryptographers acted as liaison men between the estranged War and Navy Departments) and in Berlin (where the five or six intelligence bureaus fought each other as bitterly as they did the enemy) will appreciate the achievement this feat of coordination represented. The most nightmarish problems sprang from rivalries among the military services. The army, in particular, felt its needs were being neglected in favor of the Admiralty and the RAF. The neutral tone adopted by the authors of this history scarcely disguises the ferocity of the debate over integrating the different agencies. In the British case, however, and this was their great administrative triumph, rivalries were sufficiently moderated to create an efficient intelligence apparatus that soon surpassed that of its enemies.

Growth created its own problems. Bletchley Park swelled from 200 people in 1939 to some 10,000 by the end of the war. There were rebellions against “C” that had to be quelled, clashes between SIS, MI5, and the newly created Special Operations Executive (SOE), which was set up to carry on subversive warfare and sabotage. The historian Hugh Trevor-Roper, a wartime recruit to SIS, was accused, “tried,” and acquitted for consorting with the enemy MI5. These agencies were all working in the same overseas areas and often competed for the same local agents. The battles between SIS and SOE, the bête noire of “C,” were particularly fierce. The SOE tended to use unlikely characters for agents—“from pimps to princesses,” M.R.D. Foot put it3—as well as highly irregular methods, and “C” was a regular army man. Difficulties arose not only between Bletchley Park and Whitehall but between officers and civilians, the prewar professionals and the wartime recruits. This was particularly true of SIS, which preserved a number of eccentric traditions that newcomers found faintly ridiculous and reminiscent of another age. “C” had a green light outside his room, used green ink, etc. As Enigma intelligence proved its worth and as the three armed services recruited more and more civilians into their intelligence branches, some of these problems resolved themselves. The naval tracking room at Bletchley Park, for instance, was staffed entirely by civilians.

  1. 1

    Published by Harper and Row.

  2. 2

    During the first two years of the war, the following men joined the Bletchley Park team, many to work in Huts 3 and 6 (responsible for the breaking of German air force and army Enigma) and Huts 4 and 8 (naval Enigma): Frank Adcock, F.L. Lucas, D.W. Lucas, L.P. Wilkinson, J. Saltmarsh, G.C. Morris, F.L. Birch, A.M. Turing, A.J.H. Knight, G. Barraclough, Max Newman, F.H. Hinsley, J.H. Plumb, H.O. Evennett, T.D. Jones, R.J. Getty, D.R. Taunt, W.G. Welchman, L.W. Forster, D.W. Babbage, R.F. Bennett, E.R.P. Vincent, D. Parmée, and F.J. Norton. See Tom Howarth, Cambridge Between the Wars (Collins, 1978), p. 240.

  3. 3

    SOE in France, London, Her Majesty’s Stationery Office, 1966, p. 49.

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