This film was one of a whole series of expensive box-office failures released by Twentieth Century Fox in the late 1960s, eventually leading to a major financial crisis in the company. Some time after its release, Michael Caine told interviewers that he and Bryan Forbes had both agreed to make the film because each of them owed Fox a movie under old agreements. It is highly likely that Forbes was anxious to have a box-office hit following his previous film, "The Whisperers", a very personal low-budget project which had, as he had anticipated, failed to find audiences, but which had also (as he had not anticipated) failed to win laudatory reviews, in the main. The two films Forbes had directed immediately before that - "King Rat" (1965) and "The Wrong Box" (1966) had also been flops, and rather expensive ones. A glossy heist thriller with a popular leading man must have seemed a good way for him to restore his fortunes, but it performed very badly, financially, and was, for the most part, poorly reviewed. After its failure, Forbes made an even more costly movie, "The Madwoman Of Chaillot", which was generally deemed a fiasco, both financially and artistically. Forbes continued to direct intermittently for another twenty years, but his career never recovered.
Sixth and final theatrical movie collaboration of composer John Barry and director Bryan Forbes in a movie directed by Forbes.
Vladek Sheybal (Dr. Delgado), composer John Barry, and theme song singer Dame Shirley Bassey all worked on the James Bond film franchise. Sheybal appeared as Kronsteen in James Bond 007 - Liebesgrüße aus Moskau (1963); Bassey sang the title songs for Goldfinger (1964), Moonraker - Streng geheim (1979), and Diamantenfieber (1971); and Barry composed the scores for several official James Bond movies.
Bryan Forbes got a lot of his friends to play guests at the party.