

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.
Montgomery Tully
Miss Potter
Olive Milbourne
Mrs. Booth

Arthur Hewlett
Marshall

Annette Kerr
Cinema cashier

Cleo Laine
Cleo

Dudley Moore
Rehearsal Pianist (Uncredited)