The links will take you to the IMDb (International Movie Database) listing for each film.
That Night in London (1932) Dick Warren
Men of Tomorrow (1932) Julian Angell
Cash (1933) Paul Martin (aka For Love or Money, USA)
The Private Life of Henry VIII (1933) Thomas Culpeper
The Count of Monte Cristo (1934) Edmond Dantes
The 39 Steps (1935) Hannay
The Ghost Goes West (1935) Murdoch Glourie/Donald Glourie
Knight Without Armour (1937) Ainsley J. Fothergill aka Peter Ouronov
The Citadel (1938) Dr. Andrew Manson
Goodbye, Mr. Chips (1939) Mr. Chips
The Young Mr. Pitt (1942) William Pitt/The Earl of Chatham
The New Lot (1943) (uncredited)
The Adventures of Tartu (1943) Captain Terence Stevenson, aka Jan Tartu (aka Sabotage Agent, USA, aka Tartu, USA, reissue title)
Perfect Strangers (1945) Robert Wilson (aka Vacation from Marriage, USA)
Captain Boycott (1947) Charles Stewart Parnell
The Winslow Boy (1948) Sir Robert Morton
The Cure for Love (1949) Sergeant Jack Hardacre (also director, writer, producer)
The Magic Box (1951) William Friese-Greene
Lease of Life (1954) Rev. William Thorne
The Inn of the Sixth Happiness (1958) The Mandarin of Yang Cheng
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Robert Donat 