 | Nigel Patrick Superintendent Robert Hazard |
 | Michael Craig Inspector Phil Learoyd |
 | Yvonne Mitchell Mildred |
 | Paul Massie David Harris |
 | Bernard Miles Ted Harris |
 | Olga Lindo Mrs. Harris |
 | Earl Cameron Dr. Robbins |
 | Gordon Heath Paul Slade |
 | Barbara Steele Student |
 | Peter Vaughan Detective Whitehead (uncredited) |
 | Yvonne Buckingham Sapphire Robbins |
 | Jocelyn Britton Patsy |
| Robert Adams Horace Big Cigar |
 | Desmond Llewelyn Police Constable |
 | Fenella Fielding Lingerie Shop Manageress |
 | Susan Stranks Student |
 | Freda Bamford Sgt. Cook |
 | Rupert Davies Ferris |
 | Orlando Martins Barman |
 | Harry Baird Johnnie Fiddle |
 | Grace Arnold Sapphire's Landlady |
 | Thomas Baptiste Man on the Street |
 | Victor Brooks Police Sgt. |
 | Basil Dignam Doctor Burgess |
 | Dorothy Gordon Lily |
 | Nora Gordon Newsagent's Wife |
 | Lucy Griffiths Johnnie Fiddle's Landlady |
 | Vanda Hudson Girl at Tulip Club |
 | Dan Jackson Nightclub Owner |
 | Philip Lowrie Student |
| Bartlett Mullins Newsagent |
 | Philip Ray Mr. Young |
 | Lloyd Reckord Pianist in International Club |
 | John Richardson Student |
 | Richard Vernon Doctor at Crime Scene |
| Christopher Witty Boy |
 | Dolores Mantez Student (International Club) |
| Anthony Singleton Bit Part |
| Geremy Phillips Youth |
| Joan Hooley Woman in Street |
 | Boscoe Holder Dancer in Nightclub |
| George Curtis Police Constable |
| Directing | |
| Basil Dearden | Director |
Writing | |
| Janet Green | Writer |
Costume & Make-Up | |
| Julie Harris | Costume Design |
Editing | |
| John D. Guthridge | Editor |
Camera | |
| H. A. R. Thomson | Camera Operator |
Art | |
| Carmen Dillon | Art Direction |
Camera | |
| Harry Waxman | Director of Photography |
Production | |
| Michael Relph | Producer |
Costume & Make-Up | |
| W.T. Partleton | Makeup Artist |
Sound | |
| Philip Green | Music |
| Arthur Ridout | Sound Editor |
Directing | |
| Tilly Day | Continuity |
Crew | |
| Arthur Alcott | Production Controller |
Sound | |
| Harry Fairbairn | Sound Assistant |
| John Dankworth | Musician |
Crew | |
| Lukas Heller | Additional Dialogue |
Art | |
| Dickie Bamber | Standby Property Master |
Production | |
| Douglas Pierce | Production Manager |
| Earl St. John | Executive Producer |
Directing | |
| David W. Orton | Assistant Director |
Sound | |
| Bill Daniels | Sound Recordist |
| Dudley Messenger | Sound Recordist |
