One of the things that nearly everyone knew about the late John Le Carré was that he had worked in British Intelligence, first for MI5 (domestic counter-intelligence) and then for MI6 (foreign intelligence). His life as an intelligence officer provided ample inspiration for his many novels. For years, the British Government would not even acknowledge the existence of MI5 and MI6. MI5 was first mentioned in parliament in 1952 and was recognised in law in 1989. MI6 (as well as GCHQ (signals intelligence)) were only formally acknowledged in 1994. Since then, things have changed remarkably: Stella Rimmington, a former director-general of MI5, and the first to be publicly identified as such, published her memoirs in 2001. MI5 now has a website. Richard Moore, the chief of MI6, has a Twitter account. We all know a great deal more about what the intelligence services do. Some things, however, we do not know, and we probably never will. The various iterations of the Official Secrets Act
