Codename, which premiered in April 1970, was about the secretive MI17 Spy Organisation of the same name based in the residential hall of a Cambridge College.  Eventually the series attained a more international flavour, although its base was always in Great Britain.   Primarily Codename dealt with the themes of espionage and counter-espionage at the time of the Cold War of the sixties.  Its cast contained many of Great Britain's most versatile and talented actors.