The text, from The Spy and the Traitor by Ben Macintyre, recounts the true story of Oleg Gordievsky, a high-ranking KGB officer who defected to the West. The excerpt chronicles Gordievsky's career in the KGB, highlighting his initial loyalty to the Soviet Union, followed by his gradual disillusionment and eventual decision to spy for MI6. The text describes Gordievsky's work in Copenhagen and London, his recruitment of agents and informants, and his risky operation of smuggling sensitive information to British intelligence. It further details the complex relationship between Gordievsky and his MI6 handlers, as well as the KGB's frantic efforts to uncover Gordievsky's betrayal and the eventual success of his daring escape from Moscow.