MI6: A Century in the Shadows - Heroes and Villains

BBC security correspondent Gordon Corera looks inside Britain's Secret Intelligence Service. He talks to senior intelligence officers, agents and diplomats as well as their former arch enemies about the shadowy world of espionage. What went on behind the Iron Curtain during the Cold War? MI6 Chief John Scarlett describes his clandestine meeting with an agent and the Russian defector Oleg Gordievsky talks about his reasons for coming over to the other side.