Author Graham Greene said of his novel "The Human Factor" in his 1980 autobiography "Ways of Escape" that it was "to write a novel of espionage free from the conventional violence, which has not, in spite of James Bond, been a feature of the British Secret Service. I wanted to present the Service unromantically as a way of life, men going daily to their offices to earn their pensions."
Director Otto Preminger raised the budget from outside sources instead of relying on the backing of a big Hollywood studio, as he always had in the past. When some of this independent financing fell through during filming, Preminger was forced to sell two of his Matisse paintings, and his house in the South of France, to keep the cameras rolling.
Graham Greene was extremely reluctant to sell the movie rights of his novel to director Otto Preminger, although the two men were friends. After this movie was released, he claimed that he hadn't liked any Preminger movies after Carmen Jones (1954), even though he had scripted one of them, Saint Joan (1957).
When editor Richard Trevor went unpaid, he reportedly took the negative and refused to hand it back until he got his salary.