Historical records and releases
Release of Bletchley Park and other GC&CS records
By 2004 most of the surviving records of the Government Code and Cipher School (GC&CS) had been released, following a 10-year review exercise. These records date from the beginnings of GC&CS in 1919 until VJ Day (16 August 1945), and include all wartime activity carried out from Bletchley Park. This means that virtually all surviving SIGINT or SIGINT-related records from this period have been made available for public access, regardless of subject or target.
Release of post-war historical records
Series HW 15 contains records relating to VENONA, reporting on the activities of Soviet intelligence between 1942 and 1948, complementing a release made by the National Security Agency in the United States.
Work is currently underway to review and release GCHQ intelligence reports dating from the early Cold war period, 1945-1950, on the Soviet Bloc countries, Albania, Bulgaria, Czechoslovakia, Hungary, Poland, Romania, USSR and Yugoslavia (series HW 75).