Painter, draughtsman and teacher, born in Treherbert, Glamorgan, one of the Rhondda Group, whose wife Barbara was an artist. He gained his National Diploma in Design at Cardiff College of Art, 1953; his Art Teacher’s Diploma there, 1954; and a Diploma in Art Education, University of Wales, 1967. Mainwaring completed a dissertation on the organisation of colour in children’s drawings. He taught art at Bodrinallt Secondary School, Rhondda, 1956–7; at Neath Grammar School for Girls, 1958–66; then was senior lecturer in the postgraduate art education department at South Glamorgan Institute, 1967–84. In 1987 vision in one eye, which had gradually worsened, suddenly failed and Mainwaring had to have two major eye operations and laser treatment to save his sight, leaving him with impaired vision.