Guy Rolfe
— Dr. Mark Fenton
Lisa Daniely
— Lisa Durand
Patricia Dainton
— Sister Rogers
Sydney Tafler
— Wade
Ballard Berkeley
— Inspector Austin
Anton Diffring
— Edward Shroder
Brian Worth
— Geoffrey Terry
Avice Landone
— Mrs. Terry
Eric Berry
— Col. Williams
James Raglan
— Sir Oliver Peters
Alexis Chesnakov
— Ship's Captain
Michael Golden
— Harrison
Edward Dentith
— Sergeant Lewis
Derek Aylward
William Franklyn
— Dr. Gillespie
Desmond Llewelyn
— Police Constable at Barrier