Emrys Jones as Robert Matthews / John Barlow

Zena Marshall as Ann Farrington

John Horsley as Inspector Clements

Joan Hickson as Mrs. Fenton

Hector Ross as Canning

Roger Maxwell as Col. Hector Smythe

Marne Maitland as Heinz

Ian Fleming as Dr. Wilson

Frederick Piper as Thomas Pritchard

George Pastell as Ferrari

Lesley Deane as Mrs. Smythe

Victor Platt as Sergeant