Otto Preminger - The Human Factor (1979)

When Arthur Davis, a junior bachelor in the British secret service’s African section, is seen taking a file with him -to meet his girlfriend Cynthia- the brass fears he may be the leak to Moskow, and allows Dr. Percival to terminate the ‘risk factor’ by poisoning to avoid a scandal. In fact Davis’s desk chief, Maurice Castle, is the double agent since the South African communists helped him smuggle out his black lover Sarah M., meanwhile his wife and mother of schoolboy Sam, to force him to cooperate with the Apartheid government. When Cornelius Muller, the South African official who failed to get him in Pretoria’s power, visits London for the anti-communist operation Uncle Remus, he points out Castle still is the natural suspect…