Question: Which English character actor in who appeared in British films during the 1940s, 1950s and 1960s starred in Mayerling?

Context paragraphs:
Percy Herbert (actor): Percy Herbert (31 July 1920 – 6 December 1992) was an English character actor who worked predominantly during the 1950s, 1960s and 1970s, becoming one of the most recognisable faces in post-war British cinema.

Mayerling (1968 film): Mayerling is a 1968 romantic tragedy film starring Omar Sharif, Catherine Deneuve, James Mason, Ava Gardner, Geneviève Page, James Robertson Justice and Andréa Parisy.  It was written and directed by Terence Young.  The film was made by Les Films Corona and Winchester and distributed by Metro-Goldwyn-Mayer.

Graham Moffatt: Graham Victor Harold Moffatt (6 December 1919 – 2 July 1965) was an English character actor and comedian who was most active in the 1930s and 1940s.  He is best known for a number of films where he appeared with Will Hay and Moore Marriott as 'Albert': an insolent, overweight, overgrown-schoolboy type character, loosely reminiscent of Billy Bunter.

Irene Handl: Irene Handl (27 December 1901 – 29 November 1987) was an English character actress who appeared in over a hundred British films.

George Zucco: George Zucco (11 January 1886 – 27 May 1960) was an English character actor who appeared, almost always in supporting roles, in 96 films during a career spanning two decades, from 1931 to 1951.  In his horror films, he often played a suave villain or a mad doctor.

Megs Jenkins: Muguette Mary "Megs" Jenkins (21 April 1917 – 5 October 1998) was an English character actress who appeared in British films and television programmes.

James Robertson Justice: James Robertson Justice (born James Norval Harald Justice,15 June 1907 – 2 July 1975) was an English character actor in who appeared in British films during the 1940s, 1950s and 1960s.

Leonard Mudie: Leonard Mudie (11 April 188314 April 1965) was an English character actor whose career lasted for nearly fifty years.  After a successful start as a stage actor in England, he appeared regularly in the US, and made his home there from 1932.  He appeared in character roles on Broadway and in Hollywood films.

Basil Radford: Arthur Basil Radford (25 June 1897, Chester – 20 October 1952, Westminster, London) was an English character actor who featured in many British films of the 1930s and 1940s.  He trained at the Royal Academy of Dramatic Art and made his first stage appearance in July 1924.  He is probably best-remembered for his appearances alongside Naunton Wayne as two cricket-obsessed Englishmen in several films from 1938 to 1949.

Derek Deadman: Derek Deadman (11 March 1940 – 22 November 2014) was an English character actor who appeared in numerous British films and television series for 48 years.

Supporting paragraphs: Mayerling (1968 film) James Robertson Justice
Answer: James Robertson Justice