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.
as Henry Houghton
as Gordon Lonsdale
as Elizabeth Gee
as Peter Kroger
as Helen Kroger
as Cmdr. Winters
as Marjorie Shaw
as P.O. Meadows
as Captain Ray
as Anderson
as Christina
as Captain Warner
as Chief Supt. Croft
as Supt. Woods
as Johnnie (uncredited)
as Colonel Monat (uncredited)
as Police Officer (uncredited)
as Surveillance Man (uncredited)
as Russian Embassy Official (uncredited)
as First Member at Lords (uncredited)
as Second Member at Lords (uncredited)
as Portland Official (uncredited)
as Blake (uncredited)
as News Vendor (uncredited)
as Tilly (uncredited)
