June 1940: A private plane takes off from central France, while Adolf Hitler, the would-be conqueror of Europe, prepares for a clandestine meeting near the Belgian border. It is 1979. A stolen World War II document kept secret since then is about to surface, propelling the most ruthless secret agents of Great Britain, America, Germany, and the Soviet Union into a desperate battle of wits and violence. For more than 40 years the events of this day have been Britain's most closely guarded secret. Anyone who learns them must die, his file stamped Expedient Demise, or . . . XPD
XPD is a Spy novel by Len Deighton, published in 1981, and set in 1979, roughly contemporary to the time it was written. It concerns a plan by a group of former SS officers to seize power in West Germany, in which they intend to publish some wartime documents about a (fictional) secret meeting between Winston Churchill and Adolf Hitler in June 1940, and the efforts of a British agent, Boyd Stuart, to prevent the documents becoming public.
The title is the code used by the Secret Intelligence Service in the novel to refer to assassinations it carries out, short for "expedient demise".
The novel was dramatised in eight parts by Michael Bakewell for BBC radio in 1985