Described by the FBI as 'The most complete and extensive intelligence ever received from any source'.
For twelve years, at enormous personal risk, Vasili Mitrokhin smuggled material from one of the world's most secret archives.
Reveals the identities of the KGB's top British Female agent, Melita Norwood, and the corrupt Scotland Yard officer who became a 'Romeo Spy' on four continents among many others.
Its astonishing revelations sent shockwaves through Whitehall and led to the biggest review of British security services since Spycatcher.
