William Mervyn Pickwoad (3 January 1912 – 6 August 1976) was an English actor best known for his portrayal of the bishop in the clerical comedy All Gas and Gaiters, the old gentleman in The Railway Children and Inspector Charles Rose in The Odd Man and its sequels.

Mervyn was born in Nairobi, British East Africa, but educated in Britain at Forest School, Snaresbrook, before embarking on a stage career, spending five years in provincial theatre. He made his West End debut in The Guinea Pig at the Criterion Theatre in 1946, before parts in plays such as Lend Me Robin at the Embassy Theatre, the comedy Ring Round the Moon, The Mortimer Touch, A Woman of No Importance by Oscar Wilde at the Savoy Theatre in 1953 and Charley's Aunt.