Peter Reynolds
— Stephen
Rona Anderson
— Claire
Patrick Barr
— Robert
Lana Morris
— Marion
Genine Graham
— Stella
Michael Balfour
— Joe
John Forrest
— Wally
Viola Lyel
— Mrs. Barclay
Martin Walker
— Prof. Barclay
John Le Mesurier
— Inspector
Martin Benson
— Bruno
Stephen Boyd
— Policeman (uncredited)