Colton qualified in medicine and surgery in 1960, studying at St Thomas's Hospital Medical School in London. He became a Fellow of the Royal College of Surgeons of England in 1963. He pursued a career as an orthopaedic surgeon, studying in Bristol, at the Royal National Orthopaedic Hospital in London, and at Dala Orthopaedic Hospital at Kano in Northern Nigeria during the Biafran civil war.