Codenamed 'Orphan' by his Russian recruiter, Maclean was Britain's most gifted traitor. But as he leaked huge amounts of top-secret intelligence, an international code-breaking operation was rapidly closing in on him. Moments before he was unmasked, Maclean escaped to Moscow. Drawing on a wealth of previously classified material, A Spy Named Orphan now tells this story for the first time in full, revealing the character and devastating impact of perhaps the most dangerous Soviet agent of the twentieth century.