 Margaret LockwoodFrances Gray | Frances Gray |
 Dane ClarkBill Casey | Bill Casey |
 Marius GoringCommandant Anton Razinski | Commandant Anton Razinski |
 Naunton WayneMr. Hedgerley | Mr. Hedgerley |
 Wilfrid Hyde-WhiteMr. Luke | Mr. Luke |
 Eugene DeckersAlf | Alf |
 Olaf PooleyDetective-Interrogator | Detective-Interrogator |
 Gladys HensonAttendant | Attendant |
 Paul HardtmuthPriest | Priest |
 Michael HordernLab Director Owens | Lab Director Owens |
 George BensonSandwich Stand Customer | Sandwich Stand Customer |
 Eric PohlmannJoe - the bartender | Joe - the bartender |
 John HorsleyCustoms Officer | Customs Officer |
 Patric DoonanCustoms Man | Customs Man |
| JJoan HaythorneJudy | Judy |
 Jill BalconWardress (uncredited) | Wardress (uncredited) |
 John GabrielNight Field Telephone Officer (uncredited) | Night Field Telephone Officer (uncredited) |
| HHyma BeckleyCafé Mimosa Patron (uncredited) | Café Mimosa Patron (uncredited) |
| JJohn BoxerPolice Sergeant at Customs Café (uncredited) | Police Sergeant at Customs Café (uncredited) |
 Ernest ButcherTom - Lab Assistant (uncredited) | Tom - Lab Assistant (uncredited) |
| DDaniel BrownTrain Passenger (uncredited) | Train Passenger (uncredited) |
| RRobert CawdronSoldier at Station Checkpoint (uncredited) | Soldier at Station Checkpoint (uncredited) |
 Noel JohnsonFrank Conway (uncredited) | Frank Conway (uncredited) |
 Anton DiffringOfficer at Station (uncredited) | Officer at Station (uncredited) |
| TToni FrostStewardess (uncredited) | Stewardess (uncredited) |
| CCharles HammonTrain Passenger in Platform Line-up (uncredited) | Train Passenger in Platform Line-up (uncredited) |
 Philo HauserWaiter (uncredited) | Waiter (uncredited) |
 John G. HellerSoldier at Station Check Point (uncredited) | Soldier at Station Check Point (uncredited) |
 Sam KyddCustoms Man (uncredited) | Customs Man (uncredited) |
 Richard MarnerSoldier on Train (uncredited) | Soldier on Train (uncredited) |
