made his stage debut in Aldershot in The Rascal in 1931. He joined the Old Vic theatre in London under the guidance of Tyrone Guthrie. While there he appeared in productions of The Cherry Orchard, Henry VIII, Measure for Measure, The Importance of Being Earnest, Love for Love, The Tempest, Twelfth Night, and Macbeth. Featuring in many of these were Charles Laughton and Elsa Lanchester. In the mid-1930s he also appeared at the Gate Theatre, Dublin, notably in Pride and Prejudice with Betty Chancellor. In 1933, Alexander Korda gave Mason a small role in The Private Life of Don Juan but sacked him three days into shooting. 1935–1939: Early films From 1935 to 1938, Mason starred in many British quota quickies, starting with his first film Late Extra (1935), in which he played the lead. Albert Parker directed. Mason appeared in Twice Branded (1936); Troubled Waters (1936), also directed by Parker; Prison Breaker (1936); Blind Man's Bluff (1936), for Parker's The Secret of Stamboul (1936), and The Mill on the Floss (1936), an "A" movie. Mason had a key support role in Korda's Fire Over England (1937) with Laurence Olivier and Vivien Leigh. He was in another "A", The High Command (1937) directed by Thorold Dickinson, then went back to quickies, starring in Catch As Catch Can (1937), directed by Roy Kellino. Korda cast him as the villain in The Return of the Scarlet Pimpernel (1937) 1938–1939: Television Mason began appearing in some televised productions of plays, made in the very early days of television: Cyrano de Bergerac (1938), The Moon in the Yellow River (1938), Bees on the Boat-Deck (1939), Square Pegs (1939), L’Avare (1939), and The Circle (1939). He returned to features with I Met a Murderer (1939) based on a story by Mason and Pamela Kellino, who also starred with Mason and whom he would marry. Her husband Roy Kellino directed. 1941–1947: Leading man status Second World War He registered as a conscientious objector during World War II (causing his family to break with him for many years) but his tribunal did not exempt him on the requirement to do non-combatant military service, which he also refused to perform. He appealed against that aspect of the tribunal's decision. His appeal became irrelevant once he was included in a general exemption for film work. In 1941–42 he returned to the stage to appear in Jupiter Laughs by A.