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Although the onscreen credits include a 1971 copyright statement for Michael Deeley-Peter Yates Films, Ltd., the film was not registered at the time of its release. On January 30, 1990, the company registered the film under copyright number PA-490-129. The closing credits include the following written statements: "We wish to thank the government of Venezuela, the Venezuelan Navy and Corporacion Venezolana de Guayana for their co-operation during the making of this film" and "Original radio announcements by courtesy of N.B.C. Radio."
In January 1969, just months before the publication of Max Catto's novel, Murphy's War, a Daily Variety news item reported that Buzz Kulik had bought the film rights for his company, Jeni Productions. By the following month, however, Hollywood Reporter announced that Paramount has purchased the novel. Publishers Weekly put the purchasing price "in the neighborhood of $100,000." As noted in a February 1970 Daily Variety article, the film was co-produced by Michael Deeley-Peter Yates Films, Dimitri de Grunwald's London Screenplays and Paramount, with distribution to be handled by Paramount in the U.S. and Canada and everywhere else by de Grunwald's distribution company, International Film Consortium.
As noted onscreen, the film was shot in Venezuela as well at England's Pinewood and Twickenham Film Studios. According to Filmfacts, some additional scenes were shot on Malta. Co-stars Peter O'Toole and Sian Phillips were married at the time of the production. According to the Daily Variety review, O'Toole performed many of his own stunts.