Western journalists visit Moscow to interview Adrian Harris, a former controller in British intelligence who was also a double agent for the USSR. Harris believes in both Communism and Englishness, believing himself to have betrayed his class, but not his country. The press find these beliefs incompatible, and want to find out why he became a ‘traitor’. Harris is plagued by anxieties over both his actions and his upper-class childhood, and drinks to a state of collapse.
Better known for comedic roles, Le Mesurier's casting was a brave move, one which initially concerned the actor who "was very, very scared" that "he wouldn’t be able to pull it off". Le Mesurier would later call the role 'the best part I ever had on TV'. While reviews of the play were mixed, critics were unanimous in their praise for Le Mesurier and he won the British Academy Television Award for Best Actor in 1972.