Old news in the world of surveillance and spookery today, as the original 1946 secret treaty between the UK and US which set up the famous "Echelon" listening system is finally published.
The UKUSA agreement, drafted to formalise intel-sharing arrangements which had developed during World War II, formed the basis for the US-British (and later, other nations) partnership against the Warsaw Pact through the Cold War.
The treaty dealt primarily with communications intercept information, known as signals intelligence or "sigint". Back in the early days of UKUSA cooperation, many long-distance or international phone calls were carried by longhaul HF radio, and were comparatively easily intercepted by a worldwide network of listening posts.
Later on, it is widely believed, the allied Echelon capabilities - by now mostly being provided by the US, with useful access being supplied by Britain and other nations - became able to monitor huge numbers of calls automatically, with chosen key words or phrases flagging up a given conversation for investigation by human operators.
Now released along with the Treaty itself are some intercept products garnered up to the year 1949. The cooperative publication of British files from GCHQ and other organisations has already occurred courtesy of the National Archives, here. The American end of the publications will go live on the NSA website at 3pm UK time today. ®