 This film was shot at MGMs Borehamwood Studios next door to where  the TV series _"Prisoner, The" (1967)_ (qv) was being filmed.  Prisoner star Patrick McGoohan (qv) borrowed some special effects  footage of a starry sky for his episode "Chimes of Big Ben". This  footage was not used in the broadcast version of the episode but is  visible in an early edit that was later released on video.