Jones as Professor Roderick Logan Geoffrey Keen as Gen. Bolt Robert Ayres as General Courts Jennifer Hilary as Sigrid Maurice Denham as Doctor David Davies as Captain of Galtesund Philo Hauser as Businessman Faith Brook as Woman on Bus Elvi Hale as Mrs. Sandersen Russell Waters as Mr. Sandersen Paul Hansard as German Officer (uncredited) George Roubicek as German Radio Operator (uncredited) Joe Dunne as Norwegian Quisling's Nazi (uncredited) Production Knut Haukelid wrote a memoir of the attack called Skis Against the Atom published in 1954. John Drummond wrote a novel based on the same story called But for These Men. Both books formed the basis of the screenplay. The film was originally announced in 1963. It was made by Benton Film Productions, a company of director Anthony Mann and producer S. Benjamin Fisz. Financing came from America's Allied Artists and Britain's J Arthur Rank Productions. Scenes early in the film when the main characters escape from occupied Norway were filmed around Poole and Hamworthy in Dorset with the former Channel Islands ship TSS Roebuck playing the role of the hijacked steamer. SF Ammonia was used to represent the train ferry SF Hydro in the final fjord scenes. The movie was originally titled The Unknown Battle and was to have starred Stephen Boyd and Elke Sommer and be written by Ben Barzman. Later, Anthony Perkins was announced as a star, though he withdrew. Eventually Kirk Douglas signed as the lead. Cliff Robertson was mentioned as a possible co-star before Richard Harris came on board. "I hear they are spending five million dollars, so it's got to be spectacular and that means more fiction and less fact", said Haukelid during filming. Stephen Boyd later sued Mann for half a million dollars when funding for the initial project fell apart in early 1964. "I missed out on four good roles and plenty of money when he signed me without financial backing and then dropped the project", said Boyd later. "He asked me again later but I'd made other commitments, so Kirk Douglas and Richard Harris made it under another title." Unlike the scenes in the film, the saboteurs had already left the area when the bomb exploded. Also omitted is the death of 18 Norwegian civilians in the sinking and the rescue efforts of local fishermen. Reception It was amongst the 15 most popular films at the British box office in 1966.