Although Miles continued writing "The Guinea Pig" (1948) and directing films "Chance of a Lifetime" (1950), he is best remembered for a gallery of superb character performances. Some of the most memorable included the "poor-but-honest" Joe Gargery in David Lean's "Great Expectations" (1946), the sinister phony minister/kidnapper in Alfred Hitchcock's 1956 remake of "The Man Who Knew Too Much", and the bourgeois father threatened by the prospect of his son's interracial marriage in "Sapphire" (1959).
In 1959 Miles founded the Mermaid Theater with his wife, actress Josephine Wilson. His most famous mermaid role was as Long John Silver in the annual Christmas production of "Treasure Island" which he co-wrote and starred in for a 1982 TV version. Miles was knighted in 1969 for his efforts to sustain the Mermaid Theater and was given a life peerage in 1979.