The son of Violet Eileen Concanen and Arthur De Marney, and the grandson of noted
Victorian lithographer Alfred Concanen, he appeared on the London stage from 1922 and films from 1928. It was his performance in the lead role of the play
Young Mr Disraeli at the
Kingsway and
Piccadilly theatres that brought him the offer of a long-term film contract from
Alexander Korda. He is perhaps best remembered for his starring role as Robert Tisdall, falsely accused of murder in
Alfred Hitchcock's
Young and Innocent (1937). Other early film roles include
Benjamin Disraeli, this time in
Victoria the Great (1937) and its sequel,
Sixty Glorious Years (1938). After
Young and Innocent, he alternated between leading roles and supporting parts in films. He was cast in the title role of
Uncle Silas (1947), a character part in which he played a man formerly suspected of murder who plots against his young niece, an heiress played by
Jean Simmons. After a couple more leads in self-produced films, he tended to concentrate on the theatre, taking only small roles in films and television shows. His last role was in the horror film
The Projected Man (1966). Although he had a home in
Kensington in
London, De Marney was taken ill while staying with friends at
Farnham in
Surrey. He died of
bronchopneumonia and
asthma at the nearby
Frimley Park Hospital on 18 February 1978. He was buried in the family plot at
West Norwood Cemetery in South London. ==Producer and director==