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An unprecedented look inside Britain's Secret Intelligence Service, which marks its centenary this year.
BBC security correspondent Gordon Corera talks to senior intelligence officers, agents and diplomats as well as their former arch enemies about the shadowy world of espionage.
Part Three - New Enemies
The head of Britain’s Secret Intelligence Service Sir John Scarlett, talks for the first time about the interrogation of terrorist suspects and MI6’s role in the run-up to the war in Iraq.
First broadcast on the BBC World Service on 26 October 2009.
Originally broadcast on BBC Radio 4.