A top-ranking Soviet spy turned double agent for British intelligence. A high stakes MI6 extraction that whisked him away from the KGB and into hiding. It sounds like the plot of a blockbuster film but it's the true story of a man whose actions may well have been instrumental in ending the Cold War, according to author and historian Ben Macintyre. He joins The Agenda to discuss his book on the topic, "The Spy and the Traitor: The Greatest Espionage Story of the Cold War."