Frances Gray
Margaret Lockwood
Bill Casey
Dane Clark
Sandwich Stand Customer
George Benson
Joe - the bartender
Eric Pohlmann
Customs Officer
John Horsley
Customs Man
Patric Doonan
Judy
Joan Haythorne
Wardress (uncredited)
Jill Balcon
Café Mimosa Patron (uncredited)
Hyma Beckley
Police Sergeant at Customs Café (uncredited)
John Boxer
Tom - Lab Assistant (uncredited)
Ernest Butcher
Train Passenger (uncredited)
Daniel Brown
Commandant Anton Razinski
Marius Goring
Soldier at Station Checkpoint (uncredited)
Robert Cawdron
Officer at Station (uncredited)
Anton Diffring
Stewardess (uncredited)
Toni Frost
Night Field Telephone Officer (uncredited)
John Gabriel
Train Passenger in Platform Line-up (uncredited)
Charles Hammon
Waiter (uncredited)
Philo Hauser
Soldier at Station Check Point (uncredited)
John G. Heller
Frank Conway (uncredited)
Noel Johnson
Customs Man (uncredited)
Sam Kydd
Soldier on Train (uncredited)
Richard Marner
Mr. Hedgerley
Naunton Wayne
Café Mimosa Waiter (uncredited)
Louis Matto
Operator (uncredited)
Anthony Newley
The ‘Tail’ (uncredited)
Michael Ritterman
Alan (uncredited)
Lance Secretan
Train Passenger at Checkpoint (uncredited)
Dinah Sheridan
Enemy Scientist (uncredited)
Ewen Solon
Emile Stemmler
Day Sentry at First Checkpoint (uncredited)
Robert Vossler
Customs Officer (uncredited)
John Wilder
Café Mimosa Customer (uncredited)
Billy Wilmot
Mr. Luke
Wilfrid Hyde-White
Alf
Eugene Deckers
Detective-Interrogator
Olaf Pooley
Attendant
Gladys Henson
Priest
Paul Hardtmuth
Lab Director Owens
Michael Hordern
Writer
Eric Ambler
Director
Roy Ward Baker
Original Music Composer
Richard Addinsell
Executive Producer
Earl St. John
Producer
Antony Darnborough
Director of Photography
Reginald H. Wyer
Editor
Alfred Roome