In Spies We Trust: the story of western intelligence by Rhodri Jeffreys-Jones
[PDF file]: […] people, they have tried to keep the very fact of their doing so secret – SIS, MI5 and GCHQ didn’t officially exist until 1989. By contrast, the CIA was set up by Congress, and has always been – formally at least – accountable to it. Britain came round to the same position eventually, but […]