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Spies' London is peopled with Ian Fleming's JAmes Bond and John LeCarre's George Smiley. But it's also the London of the genuine article... where for over 40 years Burgess, Maclean, Philby, Blunt and the fifth man infiltrated the British and U.S. security services and spied for the soviets. We explore that hole and corner, cloak and dagger London of MI5, MI6, and the American O.S.S, progenitor of the CIA. WE close in on the American Soviet Agent who finally confessed and unveiled the "Cambridge Ring". We pinpoint "dead letter box" and unmask the fifth man. Here, fact is really stranger than fiction. Guided by Alan.