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.

Genres

Cast

Bernard Lee

Henry Houghton

William Sylvester

Gordon Lonsdale

Margaret Tyzack

Elizabeth Gee

David Kossoff

Peter Kroger

Nancy Nevinson

Helen Kroger

Thorley Walters

Cmdr. Winters

Philip Latham

Captain Ray

Cyril Chamberlain

Anderson

Patrick Barr

Captain Warner

Derek Francis

Chief Supt. Croft

Hector Ross

Supt. Woods

Paul Eddington

Johnnie (uncredited)