News: British and US intelligence agreement revealed.

The agreement between the British and US governments to share intelligence has been described as the cornerstone of the “special relationship”, and today details of the “UK/USA” agreement have been revealed.

The National Archives has released The original 10-page document signed in 1946 in which both countries agreed to continue to share intelligence material, a practice which had begun during the Second World War.

The documents are available, free for a month, here.

The two governments agreed to share signals intelligence (sigint) produced by Bletchley Park in the UK and

The agreement says: “The parties agree to complete the exchange of the products of the following operations relating to foreign communications: (a) collection of traffic (b) acquisition of communication documents and equipment (c) traffic analysis (d) cryptanalysis (i.e. code and cipher recoveries) (e) decryption and translation (f) acquisition of information regarding communication organizations, practices procedures and equipment.

It also says: “It will be contrary to this agreement to reveal its existence to any third party whatever.”

And it is this agreement which has formed the basis for more than 60 years’ intensely close co-operation between GCHQ, as Bletchley Park became, and the giant US National Security Agency.

Later the Australian, New Zealand and Canadian sigint organizations joined the intelligence-sharing pact.

Given the huge disparity in size and budgets between GCHQ and NSA, it may appear that the benefit all flows towards the UK, but the inclusion of the Commonwealth counties and British territories all round the world meant that the UK was able to offer the US something unique.

The UK listening station in Hong Kong is reported to have been particularly of use to NSA during the Vietnam war.

A GCHQ spokesman told the Guardian: "The 1946 UKUSA agreement formed the basis for co-operation between the two countries throughout the cold war and continues to be essential in keeping the UK safe from today's threats."

Other documents released today by the National Archives include sigint reports on Soviet and Warsaw Pact military targets during the cold war, and insights into life in the Soviet Union under Stalin, and how the country was repressed.