Often the turned agents were given factual collateral with which to build up their reputations. One of the major players in the Double Cross System was Garbo, who built up a highly fictitious network of agents, and became respected by the Abwehr to the extent that they stopped landing agents in Britain after 1942, and became wholly dependent on the spurious information which was fed to them by Garbo's network.
Masterman was able to opine with some degree of accuracy that as a consequence of Double Cross's efficacy, "We [MI5] actively ran and controlled the German espionage system in this country [Britain]."
For deeper and further information on Double Cross and its significance, the reader is referred to Masterman's The Double-Cross System in the War of 1939-1945. New Haven & London: Yale University Press, 1972. [pb] New York: Avon Books, 1972. New York: Ballantine, 1982. This book is one of the most significant works in the field of literature dealing with intelligence fieldwork and although to a certain extent sanitised nevertheless remains a remarkably accurate depiction of events.
Other Double Cross Agents