A California commercial pilot sees a telecast in London of an interview with Sir Mark Lodden at his home. The Canadian is convinced that the baronet is a fraud, and he is actually a look-alike actor named Frank Welney.
Sir Mark Loddon / Frank Welney / Number Fifteen
Dirk Bogarde
Lady Margaret Anne Loddon
Olivia de Havilland
Jeffrey Buckenham
Paul Massie
Sir Wilfred
Robert Morley
Hubert Foxley
Wilfrid Hyde-White
Gerald Loddon
Anthony Dawson
The Judge
Richard Wattis
Himself
Richard Dimbleby
Dr. Schrott
Martin Miller
Maisie
Millicent Martin
Associate
Toke Townley
Editor
Deering Wells
The Guide
Bill Shine
Admiral Loddon
Ivan Samson
Michael Loddon
Sebastian Saville
The Butler
Richard Pearson
First Photographer
Robert Shaw
Second Photographer
Geoffrey Bayldon
Maddox
Gordon Sterne
Car Salesman
Arthur Howard
Miss Sykes
Joyce Carey
Mrs. Squire
Josephine Middleton
Fitch
Kenneth Griffith
Barmaid
Barbara Archer
Man at Bar
Tony Doonan
Girl in Street
Vanda Hudson
Barrister (uncredited)
Victor Harrington
Newspaper Vendor (uncredited)
Sam Kydd
Barrister (uncredited)
Reg Thomason