Tinker Tailor Soldier Spy (1979)

George Smiley, deputy to the head of the British Secret Intelligence Service, is forced into retirement in the wake of Operation Testify, a failed spy mission to Czechoslovakia. Veteran British agent Jim Prideaux has been sent to meet a Czech general, having been told the general had information identifying a deep-cover Soviet spy planted in the highest echelons of the British Secret Intelligence Service—known as the Circus, because of its headquarters at Cambridge Circus in London.

The mission proves to be a trap, and Prideaux is captured and brutally tortured by the Soviets. The Chief of the Circus, known only as Control, is disgraced for his role in Testify, and is replaced by his rival Percy Alleline. Control’s obsession with the possibility of a Soviet mole at the Circus is not shared by others in the organization, who insist that any leaks and failures at the Circus were due to Control’s incompetence. On the contrary, Alleline and the rest of the new leadership team at the Circus believe that they have a mole, code-named Merlin, working for them in Moscow Centre, the KGB headquarters, passing them secrets in an operation code-named Witchcraft. Others in the British and American intelligence communities have been impressed with the information produced by Witchcraft, and Alleline and his team are regarded as a refreshing change from Control.