What pushed Blunt, Burgess, Cairncross, Maclean and Philby into Soviet hands?With access to recently released papers and other neglected documents,this sharp analysis of the intelligence world examines how and why these men and others betrayed their country and what this cost Britain and its allies. ‘Historians fumble their catches when they study individuals' motives and ideas rather than the institutions in which people work, respond, find motivation and develop their ideas' writes Richard Davenport-Hines in his history of the men who were persuaded by the Soviet Union to betray their country.In a book which attempts to counter many contradictory accounts, Enemies Within offers a study of character: both individual and institutional – the operative traits of boarding schools, the universities of Oxford and Cambridge, the Intelligence Division, the Foreign Office, MI5, MI6 and Moscow Centre.The book refuses to present the Cambridge spies as they wished to be seen, in Marxist terms. It argues that these five men did their greatest harm to Britain not from their clandestine espionage but in their propaganda victories enjoyed from Moscow after 1951. Notions of trust, abused trust, forfeited trust and mistrust from the late nineteenth century to perestroika pepper its narrative.In a book that is as intellectually thrilling as it is entertaining and illuminating, Davenport-Hines charts how the undermining of authority, the rejection of expertise, and the suspicion of educational advantages began with the Cambridge Five and has transformed the social and political temper of Britain.