Hugh Williams
— Colin Metcalfe
Griffith Jones
— Police Inspector Gunter (as Griffiths Jones)
Deborah Kerr
— Kari Alstad
Ralph Richardson
— Frank Lockwood
Francis L. Sullivan
— Kommandant Ulrich Wettau
Roland Culver
— Cmdr. Pittwaters
Finlay Currie
— Capt. Alstad
Niall MacGinnis
— Olaf
Elizabeth Mann
— Gerda
Raymond Huntley
Patricia Medina
— Ingrid
Roland Pertwee
— Capt. Waverley
Henry Oscar
— Newspaper Editor
David Horne
— Evans, Foreign Editor
Henry Hewitt
— Jack, News Editor
John Warwick
— Milligan, Reporter in Fleet Street Pub
Brefni O'Rorke
— Political Journalist
Bernard Miles
— McAllister (Irish Soldier)
Beckett Bould
— Bergen, Spokesman of Langedal
Olaf Olsen
— Langedal's Schoolmaster
Gus McNaughton
— Army Sergeant
George Carney
— Harry, Soldier in Fleet Street Pub
John Salew
— "Man-in-the-Street" in Fleet Street Pub
Meriel Forbes
— Milly, the Barmaid
Philip Friend
— Pilot
George Merritt
— German Trawler Captain
John Boxer
— U-Boat Commander
H Victor Weske
— Heinrich
Gerhard Kempinski
— Barman, Bia Tonne in Oslo
George Spence
— Norwegian Villager (uncredited)