- Unknown:
- Lance Sieveking
- Produced By:
- David H. Godfrey
- John Cavendish:
- Norman Claridge
- Arthur Hastings:
- Gordon Davies
- Evelyn Howard:
- Beatrice Gilbert
- Mary Cavendish:
- Marjorie Mars
- Dorcas:
- Elsa Palmer
- Mrs Inglethorp:
- Courtney Hope
- Alfred Inglethorp:
- Carl Bernard
- Cynthia Murdoch:
- Annette Kelly
- Hercule Poirot:
- Austin Trevor
- Lawrence Cavendish:
- John Glen
- Dr Wilkins:
- George Merritt
- Manning:
- Stephen Jack
- Mr Wells:
- Charles Spencer
- Mace:
- Charles Hodgson
- Det -Insp Japp:
- Manning Wilson
- Supt Summerhaye:
- Owen Berry
- Mr Philips, k c:
- Brian Haines
- Sir Ernest Heavywether, k c:
- Jeffrey Segal
