Documents declassified by GCHQ and the US National Security Agency in 2010, relating to the establishment of US-UK intelligence sharing agreements in the postwar era.
In April 2010, the US National Security Agency (NSA) declassified a tranche of documents relating to the wartime intelligence sharing between the UK and the US and the formalising of intelligence sharing in the immediate postwar period. This was followed in June 2010 with the release of similar papers by GCHQ to The National Archives in the UK. Together, these declassifications marked the first time that the existence of a bilateral agreement was publicly avowed. They also confirmed the sheer extent of US-UK intelligence sharing, as formalised from 1946 onwards, which later grew to incorporate the Five Eyes alliances (with Canada, Australia and New Zealand).
This collection brings together the documents proactively released by the UK and US governments in 2010. Much of this material relates to the establishment and signing of the original British-US Communications Agreement in March 1946 (the so-called BRUSA Agreement), and the ways in which this agreement emerged from the wholesale exchange of wartime intelligence from 1940 onwards. The disclosures include the text of the BRUSA Agreement and its technical appendices as they developed between the late 1940s and early 1950s. They also include documents relating to the later development of BRUSA into the 1956 UKUSA Agreement – a broad framework which continues to shape contemporary US-UK intelligence sharing practices as well as the exceptionally close relationship between the Five Eyes intelligence agencies.
