In 1973, an indiscretion by a Soviet operative in Hong Kong confirms the existence of the mole to Oliver Lacon, the Civil Service overseer of the Circus in Whitehall. Smiley is recalled from retirement to investigate and ultimately unmasks Haydon after a tortuous, soul-searching quest. Under interrogation, Haydon reveals much of his secret past to Smiley and plans are set in motion to exchange Haydon for Western agents held in the Eastern Bloc, but before this happens he is killed while still in Circus custody. It is strongly implied, though never stated, that the killer was Prideaux.