Barbara Parkins was going to be in this movie, but was replaced by Virginia McKenna before filming began.
Donald Sutherland had played supporting parts (mostly small) in Britain for nearly ten years before his roles in "The Dirty Dozen" and "Joanna" brought him to Hollywood's attention. When he began receiving American offers, he had a problem, which was that he simply didn't have the money to fly out to California and support himself and his family until deals were finalized. He turned to fellow-Canadian Christopher Plummer, with whom he had worked in both "Hamlet" for television and "Oedipus The King" for the cinema. Despite the fact that they knew each other only slightly at that time, Plummer advanced him $5000, and Sutherland's Hollywood career began.
The 91 minute version was approved by director Stuart Cooper, but has no idea when it was done or who supervised it. On the Blu-ray liner notes by Julie Kirgo, Cooper suggests that it may have been producer and actor David Hemmings.
Christopher Plummer and David Warner would later appear together in Star Trek VI: The Undiscovered Country (1991) and Star Trek: Klingon Academy (2000) as Klingon leaders General Chang and Chancellor Gorkon.
Director Stuart Cooper said in an interview that the 81 minute version is "a disaster", and said that much to the producers when they screened it for him.