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Ian Hunter as Detective Inspector Gregory |
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Austin Trevor as Leopold Dryden |
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Lilian Oldland as Joan Dryden |
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Henry Kendall as Rodney Fleming |
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Val Gielgud as Julian Caird |
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Peter Haddon as Guy Bannister |
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Betty Ann Davies as Poppy Levine |
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Jack Hawkins as Herbert Evans |
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Donald Wolfit as Sydney Parsons |
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Robert Rendel as Sir Herbert Farquharson |
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Gordon McLeod as Chief Commissioner |
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Hannen Swaffer as Hannen Swaffer |
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Vernon Bartlett as Vernon Bartlett |
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Eric Dunstan as Eric Dunstan |
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Gillie Potter as Gillie Potter |
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Elisabeth Welch as Elisabeth Welch |
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Eve Becke as Eve Becke |
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Gershom Parkington as Gershom Parkington |
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Percival Mackey as Percival Mackey |
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Ivor Barnard as Joseph Higgins (uncredited) |
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Cecil Bevan as Police Doctor (uncredited) |
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George De Warfaz as Foreigner (uncredited) |
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Howard Douglas as Weisskopf (uncredited) |
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Arthur Hambling as Man on BBC Reception Desk (uncredited) |
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Vincent Holman as Detective (uncredited) |
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Bruce Lester as Peter Ridgwell (uncredited) |
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Percy Rhodes as Wife's Lover on Broadcast (uncredited) |
| Directing | Reginald Denham | Director |
| Camera | Günther Krampf | Director of Photography |
| Editing | Reginald Beck | Editor |
| Writing | Basil Mason | Adaptation |
| Writing | Val Gielgud | Novel |
| Directing | Vincent Permane | Assistant Director |
| Sound | John Cox | Sound Recordist |
| Costume & Make-Up | Colin Becke | Costume Design |
| Writing | Eric Maschwitz | Novel |
| Production | Hugh Perceval | Production Supervisor |
| Art | R. Holmes Paul | Art Direction |
| Sound | Geoffrey Goodheart | Music Director |
| Sound | Ord Hamilton | Original Music Composer |
