The film is based on the actual events of the Portland Spy Ring trial in the U.K. A disgruntled Navy Clerk is transferred to a secret research establishment and is subsequently black-mailed/paid by Czech intelligence to procure secrets for them. He seduces the secretary who controls the most secret documents, and they enjoy the fruits of their treachery until the British authorities begin to close in on them.
Writer: Peter Barnes, Frank Launder
Director: Robert Tronson
Producer: Leslie Gilliat
Director of Photography: Arthur Lavis
Henry Houghton
Gordon Lonsdale
Elizabeth Gee
Peter Kroger
Helen Kroger
Cmdr. Winters
Marjorie Shaw
P.O. Meadows
Ring of Spies (1964) Original Trailer [FHD]