The new film adaptation of Tinker Tailor Soldier Spy, premiered at the Venice Film Festival last week, has been praised for its atmospheric depiction of 1970s London. But how firmly is John Le Carre's novel rooted in reality?
(Spoiler alert: Key plot details revealed below)
Trying to establish the precise relationship between John le Carre's fictional depiction of British intelligence in Tinker Tailor Soldier Spy and its real life counterpart is a task that requires the investigative skills of George Smiley.
And even le Carre's fictional spymaster might be left wondering if he had unpeeled all the layers of mystery to get to the real truth.
It is not unusual for writers to draw on the real world and their own experiences and then shape it into fiction. But Le Carre is different. He draws on his own experience of the secret world for his work.
And because that world - and le Carre's own career in it - is out of sight and clandestine, the reader is left wondering, far more than usual, where fact ends and fiction begins.
http://www.bbc.co.uk/news/magazine-14846154
Note: 11 September 2011 Last updated at 00:11 GMT