 James MasonRichard Francis Heritage | Richard Francis Heritage |
 Joyce HowardLaura Verity | Laura Verity |
 Tom WallsChristopher Child | Christopher Child |
 Phyllis StanleyLily Bernard | Lily Bernard |
 Edward RigbyMansel | Mansel |
 Ronald WardCarter | Carter |
 David FarrarCommander Lippinscott | Commander Lippinscott |
 Karl StepanekRiccardo | Riccardo |
 Betty WarrenFay | Fay |
 Walter CrishamCharlie | Charlie |
 Jeanne De CasalisLady with Dog | Lady with Dog |
 Patricia MedinaMary, Manicurist (as Pat Medina) | Mary, Manicurist (as Pat Medina) |
 George RobeyPawnbroker | Pawnbroker |
| RRonald ChesneyMax - Mouth Harmonica Player | Max - Mouth Harmonica Player |
| PPeggy DexterBobby | Bobby |
 Finlay CurrieMerchant Captain | Merchant Captain |
 Brefni O'RorkeDetective Inspector Burrows | Detective Inspector Burrows |
| EEric MasonBenson - Illusionist | Benson - Illusionist |
| AAnthony HollesHotel Hairdresser | Hotel Hairdresser |
 Ian FlemingNot listed | Not listed |
 Kynaston ReevesNaval Officer in Charge of Court Martial | Naval Officer in Charge of Court Martial |
 Herbert LomasVan Driver | Van Driver |
| PPercy WalshPolice Sergeant | Police Sergeant |
 Terence de MarneyCode Expert | Code Expert |
| EElizabeth FlatauNot listed | Not listed |
 Charles VictorPub Owner | Pub Owner |
| RRobert SansomPetty Officer Bill Grant | Petty Officer Bill Grant |
| AAlvar LiddellBoothby - Radio Announcer | Boothby - Radio Announcer |
 Anthony Dawson2nd Code Expert | 2nd Code Expert |
| AAlf GoddardOne of Mansel's Tough Friends (uncredited) | One of Mansel's Tough Friends (uncredited) |
