TCM overview:

Accomplished stage performer, for many years president of the actors organization Equity, who entered film in the early 1930s and often played doddering clerics, bureaucrats or schoolteachers. Aylmer was twice cast as the Archbishop of Canterbury (in “Henry V” 1944 and “Becket” 1964) and played Polonius in Laurence Olivier’s film, “Hamlet” (1948). He was knighted in 1965.