A government team researching cures for plague find their results put on the Official Secrets list. One of their number is so incensed by this that he lets the maimed and jealous companion of a female colleague draw him into what, technically, could be a treasonable act. Tony Britton ... Dr. Robert Marriott Virginia Maskell ... Dr. Lucy Byrne Ian Bannen ... Alan Andrews Kenneth Griffith ... Dr Shole Peter Cushing ... Professor Sewell Thorley Walters ... Special Agent Prince Donald Pleasence ... Parsons, alias Bill Brown Spike Milligan ... Arthur, lab orderly Raymond Huntley ... Sir George Gatting, the Minister of Defense Sam Kydd ... Slater Anthony Booth ... Parkin Basil Dignam ... Dr.Childs Brian Oulton ... Director Robert Bruce ... Levers John Payne ... Iverson