After attending Aldenham School in Elstree, Hertfordshire, Arthur received an MB and BChir at Cambridge University. He did National Service on the front line in Korea, as a medical officer in support of the Durham Light Infantry. Post-registration posts followed in Birmingham, London, Newcastle and Plymouth, and he obtained the MRCP in 1957. He worked as a senior paediatric registrar in Ibadan, Nigeria, and then in Bristol.