michael caine, who at this early stage in his career was primarily playing bit parts, was originally up for the role of private henry hook, which went to james booth. according to caine, he was extremely nervous during his screen test for the part of bromhead, and director cy endfield told him that it was the worst screen test he had ever seen, but they were casting caine in the part anyway because the production was leaving for south africa shortly and they had not found anyone else for the role. caine also believed that he was fortunate that the film was directed by an american (endfield), because "no english director would've cast me as an officer, i promise you, not one," due to his cockney roots.