‘Because I Don't Trust Him,We are Friends’: Signals Intelligence and the Reluctant Anglo-Soviet Embrace, 1917–24

Signals intelligence was crucial in helping British policymakers come to grips with Communist subversion – real or imagined – in this country. Still, though released by GCHQ in the late 1990s, Soviet diplomatic intercepts have yet to feature prominently in any study of early Anglo-Russian relations. While they ought not to be regarded on their own as the definitive source on Soviet foreign policy, GCCS intercepts tell us a great deal not only about how Moscow used the threat of subversion as a bargaining chip but also about personalities and bureaucratic rivalries on the Soviet side.