Artist who employed computers, born in Stockport, Cheshire, who studied at Reading University, 1967–71, then worked in Holland on a Royal Netherlands Government Scholarship, 1971–2. He began to use computers to organise visual ideas in 1973, from 1974–7 doing research using computer facilities at Hatfield Polytechnic, backed by Arts Council funds. Exhibitions included Space, at Abbot Hall Art Gallery, 1976; The Constructive Context, Arts Council tour, 1978; and Non-Standard Constructions, a three-man show at Museum of Modern Art, Oxford/Gardner Centre Gallery, Brighton, in 1980. Research Machines of Oxford made equipment available for Longson’s works there. Arts Council, Reading University and several Dutch collections acquired examples.