GCHQ. Richard Aldrich

to Eastcote was undertaken during early 1946 in four main parties. The first was the priority group, and included the Soviet and East European Division; the last arrived in April 1946.⁶⁵ Staff turning up in leafy Pinner in search of lodgings were allowed to refer to their place of work as ‘GCHQ’, but they were told firmly that any reference to ‘signals intelligence’ was forbidden.⁶⁶ Between 1945 and 1948 the term ‘GCHQ’ was used interchangeably with both ‘London Signals Intelligence Centre’ and ‘Station X’.⁶⁷

      Bletchley Park was now an empty shell in the Bedfordshire countryside. Barbara Abernethy, who had worked as Denniston’s personal assistant, recalls: ‘We just closed down the huts, put all the files away and sent them down to Eastcote. I was the last person left at Bletchley Park. I locked the gate and took the key down to Eastcote. That was it.’⁶⁸ Much of the machinery was broken up, including examples of the mighty ‘Colossus’ computational machine. However, Professor Max Newman, who had been central to its development, managed to secure two ‘Colossus’ machines for his new computing department at Manchester University. These were transported by the Ministry of War Transport at the price of thirty-four shillings a ton. Newman offered to send a junior university lecturer down ‘to sit on the van’ to make sure that the precious machines were not damaged in transit.⁶⁹ In fact, this was not quite the end of Bletchley Park’s active life in sigint, since GCHQ continued to use it for training courses as late as the 1960s.

      The intention behind GCHQ’s post-war move to London was to service the centres of power in British government. Accordingly, in the autumn of 1945 Travis took the opportunity to look at how the sigint product – the ‘blue jackets’ or ‘BJs’– circulated around Whitehall. The Foreign Office was a big customer, receiving three sets of BJs daily. One set stayed with Ernest Bevin, the new Foreign Secretary and his war-weary Permanent Under-Secretary, Cadogan, ‘for their immediate information’. Another went to the Services Liaison Department, which worked closely with the JIC. The third went to the main departments. Virtually everyone in the operational core of the Foreign Office habitually saw BJs, but they were always kept separate from other documents in special boxes which were locked up overnight.⁷⁰

      In MI5, the ritual of sigint security was closely observed. Distribution was presided over by the redoubtable ‘Mrs Arbuthnot’, who recorded everything meticulously in her log. Security of BJs seems to have been at its most lax inside SIS, where batches of them circulated around sections for as long as six weeks before being returned. Nor were they properly logged. GCHQ noted that, quite uniquely, inside SIS BJs were never treated as requiring special security measures, and indeed in some cases had ‘found their way into the General Office for filing’. This broke the cardinal rule that sigint was never to mix with ordinary paperwork.⁷¹

      The first major international crisis of the Cold War era was not long in coming. In June 1948, the Soviets decided to block road and railway access to the western sectors of Berlin, which were controlled by the British, the French and the Americans. The Berlin Blockade was defeated by a massive airlift of some four thousand tons of supplies a day. Hidden amongst the innumerable supply flights heading to Berlin were anonymous but highly secret aircraft collecting sigint for GCHQ, which provided some of the best intelligence during the crisis. Even before the crisis ended in May 1949, GCHQ had already been working hard on the ‘Russian problem’ for almost five years. The early onset of the Cold War had not only provided GCHQ with new targets, but had helped to perpetuate the wartime alliance between British code-breakers and their counterparts in allied countries. This, as we shall see, was fundamental to the postwar success of GCHQ.

       4 The KGB and the Venona Project

       …Paul [Guy Burgess], and Yan [Anthony Blunt] consider that the situation is serious.

      Message from the KGB station in London to Moscow,

      February 1950¹

      The ‘Venona Project’ was possibly the most astounding code-breaking effort of the early Cold War.² Employing perhaps no more than a hundred people, it exploited a weakness in KGB communications and decoded some of the messages sent by Soviet intelligence. As a result, it revealed key Soviet agents and illuminated the unexpectedly vast scope and scale of KGB espionage in the West during the 1940s. This material was so significant that even though no new messages were collected after 1948, British and American code-breakers continued to work on the residue until October 1980. Initiated by the Americans, Venona collected new partners – first the British, and later the Australians, the Canadians, the Dutch and even the ‘neutral’ Swedes. It is justly famous for revealing some of the ‘giants’ of Russian espionage, including Klaus Fuchs and Donald Maclean, but the vast pool of messages that remain unsolved is also significant. Even now, it points unambiguously to many other cases yet to be resolved.

      Anxiety about the compromise of sigint secrets was always central to the code-breaking profession. Back in 1927, Prime Minister Stanley Baldwin’s infamous exposure of the reading of Soviet high-grade systems in the House of Commons had taught a whole generation of interwar code-breakers the price of careless talk. Thereafter, anxiety about the Ultra secret persuaded more than ten thousand people to keep their wartime vow of silence for decades. However, Venona introduced an even greater level of paranoia, since it hinted at the possibility of hundreds of Soviet agents active inside the governments of the West, some in high positions. For this reason it is unlikely that Venona was ever made known to President Roosevelt, and it was three years before his successor, Harry Truman, was let into the secret. Clement Attlee, Britain’s first post-war leader, was not told until a major security case made it unavoidable in late 1947.³ Nevertheless, the Venona project was compromised by several Soviet agents within five years of its initiation. This did not entirely negate its value, since the Soviets could not prevent the West from continuing work on the immense volume of KGB messages that had already been collected during the 1940s, patiently revealing the names of important agents. In the late 1950s, for example, GCHQ suddenly began to have success with Soviet Naval Intelligence messages, having used a new analytic technique.⁴

      The extreme secrecy of the Venona project was its Achilles heel. Although the material often pointed to the identity of Soviet spies in the West, for security reasons it could not be shown to those arrested to persuade them to confess; still less could it be produced in court. Any sensible defence lawyer would seek to probe the nature of Venona, not only exposing its fragmentary nature, but also revealing sensitive secrets about sigint. Therefore, once spies had been identified by Venona, they had to be either caught red-handed meeting with their KGB controller, or successfully interrogated and broken. The result was a game of cat and mouse in which the mouse sometimes got away. In 1951, Donald Maclean, Guy Burgess and John Cairncross were among those who escaped by a whisker. Remarkably, Theodore Hall, an American Communist spy within the atomic programme, also brassed it out, despite close interrogation, escaping what would almost certainly have been death in the electric chair.⁵ By contrast, in 1950 the atom spy Klaus Fuchs succumbed to repeated and patient questioning by MI5 after his arrest. He told his interrogators that he ‘supposed he would be shot’, and was pleasantly surprised when he wasn’t.⁶

      Venona revealed the security-minded nature of the Soviets. Much of their traffic was encrypted using a one-time pad system. This was time-consuming and slow, but they were willing to put in vast effort to protect their communications. This required