[2013]

I was an intelligence official from 1952 to 1987, almost the whole duration of the Cold War. On reflection I would now describe that historical period in two ways. The first is a particular succession of international events, in which intelligence knowledge usually played a significant part, or when intelligence collection provoked events. The second is a mental state of permanent rivalry between East and West, with its set of attitudes, fears, ambitions, adversary images, precautions and preparations on both sides. The West was heavily dependent on intelligence because of the Soviet regime's ferocious secrecy, while the Soviets refused to believe anything they had not learned by secret means. The result was an intelligence war of great intensity, which incidentally established intelligence organisations as a substantial element of the peacetime Western state.

How did Sigint fit into this general picture? We now have the authorised history of GCHQ; in conjunction with earlier accounts of the US National Security Agency (NSA), including the redacted version of Thomas Johnson's internal history, it can be said that Western Sigint has finally been given a place in the post-1945 historical record. Partly because the Soviet intelligence archives remain inaccessible, the evidence is still incomplete at what we might call the technical-cum-strategic level of the intelligence war: the constant game of snakes and ladders between intelligence and secrecy in East and West, the mixture of advances and defeats for each side, and the cumulative effects they had on policy-making. There is also always something of a tension between the historian's judgement and one's own memories of events – fallible, distorted, yet with the conviction that ‘I was there’. I therefore confine myself to some generalisations of Cold War Sigint which may help historians to draw conclusions from the evidence they get as more materials become available. I rely on official revelations about Sigint, particularly those of the US, and cite relevant observations from Professor Ferris's history without seeking to elaborate on them.

First, the size of the post-war effort: GCHQ was easily the biggest UK agency. Why so big compared with the others? Resources were not planned in 1945 on a community basis, and there was never a proper intelligence community budget until the Cold War was over.