John Michael Dinham was born in Taunton on 19 February 1936, the son of Alfred Dinham, a motor engineer, and Elsie Winifred, née Pike. He was educated at Taunton School and at St Mary's Hospital Medical School. After qualifying in 1960, he was appointed house surgeon at St Mary's Hospital and he subsequently trained in orthopaedics at St George's Hospital, London. He took his FRCS in 1967 and was later appointed consultant orthopaedic surgeon to Mount Gould Hospital, Plymouth. He was a member of the British Orthopaedic Association and published articles on patellectomy for osteo-arthritis, traumatic discitis, trigger thumb and popliteal cysts in children. He was a good games player (golf and rugby), enjoyed swimming, and had an interest in philately. He married twice, in 1961 and in 1984, having one son and one daughter by his first marriage. He died, at the early age of 50, on 25 August 1986. His second wife, Joan, survived him, but they had no children.