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.
Dirk Bogarde
as Sir Mark Loddon / Frank Welney / Number Fifteen
Olivia de Havilland
as Lady Margaret Anne Loddon
Paul Massie
as Jeffrey Buckenham
Robert Morley
as Sir Wilfred
Wilfrid Hyde-White
as Hubert Foxley
Anthony Dawson
as Gerald Loddon
Richard Wattis
as The Judge
Richard Dimbleby
as Himself
Martin Miller
as Dr. Schrott
Millicent Martin
as Maisie
Toke Townley
as Associate
Deering Wells
as Editor
