A composer (Laurence Payne) is stuck in a middle-class marriage and finds that his affair with his wife's half-sister (Jane Griffiths) has resulted in a pregnancy. When his wife refuses to give him a divorce he hatches a murder scheme that is too clever by half.
Unfortunately the movie The Third Alibi is not yet available on Disney Plus.
| Costume & Make-Up | Evelyn Gibbs | Wardrobe Master |
| Directing | Montgomery Tully | Director |
| Writing | Maurice J. Wilson | Screenplay |
| Writing | Montgomery Tully | Screenplay |
| Writing | Philip Baker | Theatre Play |
| Writing | Jane Baker | Theatre Play |
| Editing | Jim Connock | Editor |
| Camera | John Shinerock | Camera Operator |
| Production | Maurice J. Wilson | Producer |
| Sound | Don Banks | Original Music Composer |
| Camera | Walter J. Harvey | Director of Photography |
| Art | William Hutchinson | Art Direction |
| Costume & Make-Up | Hilda Fox | Hairdresser |
| Costume & Make-Up | Richard Mills | Makeup Artist |
| Production | Pat Marsden | Production Manager |
| Directing | David Tringham | First Assistant Director |
| Sound | Dick Smith | Sound Recordist |
| Sound | Philip Martell | Music Director |
| Directing | Estelle Stewart | Continuity |