GCHQ. Richard Aldrich

2 Friends and Allies

       …there is no better analogy than the schoolboy with his stamp collection.

      GC&CS, discussing intelligence cooperation with the Russians in 1943¹

      The most secret aspect of Bletchley Park’s wartime work was its dealings with friends and allies. Many have pondered whether the British attacked Soviet codes and cyphers during the Second World War. The official history of British intelligence insists that Churchill ordered this activity to stop in June 1941, following Hitler’s invasion of the Soviet Union, since Moscow had suddenly become an ally.² However, it is now clear that this is quite untrue. At the end of October 1941, intelligence chiefs were actually discussing the expansion of the sigint organisation in India, which was then dealing with ‘material from Russian, Persian and Afghan sources’. Remarkably, it was not yet working on German traffic.³ Moreover, in January 1942, and again in early 1943, the British and the Americans were discussing the mutual exchange of intercepted material from ‘Slavic nations’.⁴ Soviet cyphers had been the core business for Britain’s interwar code-breakers, and work on this material never stopped completely during the Second World War.

      To understand why, we must cast our minds back to the approach of the war. During the 1930s, GC&CS continued to follow the traffic of the Comintern even after other Soviet systems were lost. This revealed persistent efforts to subvert the British Empire in locations such as India, Malaya and Hong Kong. Indeed, the Soviet Union appeared to be in league with Germany after the Nazi–Soviet Pact of August 1939. It is often forgotten that Poland was invaded by Germany and the Soviet Union together. For a nightmare period between August 1939 and June 1941, many suspected that Germany, Italy, Japan and the Soviet Union would act in uneasy concert, dividing the spoils of the world between them. This was precisely the plan that Germany’s Foreign Minister, Baron Joachim von Ribbentrop, was trying to press upon his irascible master. However, in the end Adolf Hitler’s racist outlook could not tolerate the idea of alliance with the Slavic peoples, and he had always declared his desire for ‘Lebensraum’ in the east.⁵

      Throughout this dangerous period, before Hitler and Stalin turned upon each other, the Soviet Union remained a key intelligence target. SIS even organised a secret squadron to conduct aerial reconnaissance of possible bombing targets deep inside southern Russia, notably the oilfields. GC&CS developed close relations with code-breakers in the Baltic states who were also working on Soviet codes. A month after the outbreak of war with Germany, Clive Loehnis, a naval officer at GC&CS (who would become Director of GCHQ in the 1960s), told Alastair Denniston that additional premises were needed to cope with the increase in the interception of Soviet military traffic, so new buildings were erected at Scarborough.⁶ With the military chiefs keen to ‘get cracking on Russian traffic’, Denniston began a unique and profitable experiment. In 1939 GC&CS sent a party of British sigint operators to Sweden to work secretly out of the British Embassy in Stockholm, where there was better radio reception from Russia. The creation of this forward listening station was fortuitous, since Stalin embarked on the Winter War against Finland in November 1939, and GC&CS enjoyed a front-seat view of the whole proceedings.⁷

      John Tiltman remained the key figure in the effort against Soviet communications. A colonel in the King’s Own Scottish Borderers, he was noted for his smart uniform, which included tartan trews. However, as the war progressed he came under the influence of the spirit of Bletchley Park, and was often seen in a baggy pullover and green corduroy slacks.⁸ One of his first duties was to visit Helsinki to conclude a deal with the talented Finnish code-breakers. Britain funded the expansion of the Finnish cryptographic bureau, and supplied it with the latest equipment in return for material on the Soviets. In March 1940, after imposing a series of humiliating defeats on the Soviets, the Finns signed the Moscow Peace Treaty, ceding about a tenth of their territory.⁹ The sigint deal with the British was unaffected, and indeed in September 1940 its scope was expanded during a visit by Admiral Godfrey, the Director of Naval Intelligence. According to an internal GC&CS history written after the war, ‘The Finns had agreed to supply us with copies of all their intercepts and cryptographic successes, provided that we did the same.’ Preceding the agreement with the Americans by more than a year, this was perhaps Britain’s first comprehensive sigint alliance.¹⁰

      By March 1940, the interception of Soviet traffic was big business. For the first time, collection began in the Middle East, at Sarafand in Palestine, although it was still sent to India for analysis. Soviet traffic was also being taken at Ismailia in Egypt and Dingli in Malta. Meanwhile, in Hong Kong, other British sigint operators were also listening to the Soviets before they packed up their equipment to move to Singapore in anticipation of a Japanese attack. The surge of Soviet traffic meant changes were required at GC&CS, where an inter-service Soviet section was created to work in close conjunction on naval, military, air, diplomatic and commercial material. After the fall of France in the summer of 1940, evacuated French cryptographers joined the effort on Soviet traffic at GC&CS. A Polish section, based at Stanmore on the northern fringes of London, soon discovered that it was able to listen in to Soviet traffic as far away as Ukraine.¹¹

      Ultra had provided Bletchley Park with an intimate picture of the build-up of German forces in the east, prior to their attack on the Soviet Union. As early as January 1941 it was clear that Hitler’s vast armies were being moved eastwards in preparation for some grand project. Yet even with the evidence of many German divisions massing in the east, Whitehall refused to believe that Hitler was mad enough to deliberately opt for war on two fronts. Like Stalin himself, the British Chiefs of Staff believed that this was more likely to be a prelude to a German ultimatum, a bluff in which Hitler would demand the cession of some further territory in Eastern Europe. Throughout early 1941, Stalin believed that all war warnings were self-serving efforts at deception by the West, which sought to provoke a war between Germany and the Soviet Union. Stalin has frequently been ridiculed for ignoring the warning signs of the impending attack, but despite the benefits of Ultra, it was only the month before the fateful date of 22 June 1941 that British intelligence chiefs realised what was about to occur.¹²

      Hitler’s decision to turn east was a fabulous stroke of luck for Britain. At a time when its forces were struggling, this was a most welcome redirection of the main German war effort. Taken together with Pearl Harbor at the end of the year, it is right to regard 1941 as nothing less than the fulcrum of the war. However, Bletchley Park now faced a new problem. Should it pass sensitive intelligence derived from Ultra to the new Soviet ally, which had been a dedicated enemy of Britain since 1917? The idea that two of Britain’s adversaries were about to fight to the death filled most military intelligence officers with ill-disguised glee. Many argued that passing sigint to the Soviets was pointless, since few expected them to hold out later than 1942. Others insisted that not even Ultra could penetrate the fog of self-deception with which Stalin had surrounded himself.¹³

      In the event, Bletchley Park did develop a precarious sigint liaison with the Soviets. When the British Chiefs of Staff despatched a military mission to Moscow, the code-breakers decided to work through it to find out what the Soviets were doing. They began cautiously, asking about ‘low-grade material only’, notably German Air Force three-letter tactical codes. They intended to send an officer from Bletchley, and in the long term even hoped to persuade the Soviets to accept a British Y unit, or forward listening station, that would intercept German tactical messages on their front. In late 1941 the Soviets agreed to a visit from