Irish sculptor born in Banbridge, County Down. He studied painting at Belfast School of Art and at the Slade School of Fine Art in London (1928–31) before turning to sculpture in the early 1930s. His earliest wood carvings were influenced by archaic and primitive art, especially by African sculpture, and by Brancusi's pure reduction of figurative forms, as in Figure (1937; Brit. Govt A. Col.). After 1936 his work became increasingly Surrealist in spirit, and he was loosely associated with the British Surrealist group; Eye, Nose and Cheek (h. 889 mm, 1939; London, Tate) and other stone carvings of 1938–9 constitute an important contribution to Surrealist sculpture. After spending most of World War II in service in India, McWilliam returned to London to teach at Chelsea School of Art and at the Slade, and he resumed working in a great variety of media, including terracotta, stone, wood and bronze. He joined the London Group in 1949, RBA in 1950 and was elected an RA associate in 1959, resigning four years later. Among McWilliam's many commissions were The Four Seasons for the Festival of Britain, 1951; Father Courage for Kent University at Canterbury, New Zealand, 1960; and Hampstead Figure at Swiss Cottage, London, 1964. During the 1950s his work progressed from an attenuated, broken-surfaced figuration towards more hieratic symbolic forms, while retaining a characteristically fantastic or ironic aspect. His mechanomorphic bronze figures of the early 1960s dynamically parody the reclining figures of his friend Henry Moore, while the Bean sculptures of 1965–6, with their swelling organic forms, at once celebrate and satirize sexuality. McWilliam's output is typified by a capricious and fanciful imagination, combined with a predisposition to work in series, exhaustively exploring a theme and then making a radical change in subject and style. His work is represented in many major national collections including the Tate Gallery, London and Museum of Modern Art, New York. Retrospectives held at Arts Council of Northern Ireland, 1981 and Tate Gallery, 1989. Lived and worked in London.