I was twenty-five when, in 1956, I was formally inducted into MI5 as a junior officer… Spying on a decaying British Communist Party twenty-five thousand strong that had to be held together by MI5 informants did not meet my aspirations. Neither did the double standards by which the Service nurtured its own. MI5, for better or worse, was the moral arbiter of the private lives of Britain’s civil servants and scientists. Under the vetting procedures of the day, homosexuals and other perceived deviants were held to be vulnerable to blackmail, and consequently debarred from secret work. But the Service seemed quite content to ignore the homosexuals in its own ranks, and its Director General openly cohabiting with his secretary during the week and his wife at weekends, even to the point of leaving written instructions for the night duty officer in case his wife called up wanting to know where he was. Yet God help the registry typist whose skirt was deemed too short or too tight, or the married desk officer who gave her the eye.

John Le Carré, “The Pigeon Tunnel: Stories from My Life”.