John Laurence Mercer was a consultant cardiothoracic surgeon at Broad Green and Fazakerley hospitals, Liverpool. He was born in 1932, the elder son of Major Laurence Walter Mercer, studied medicine at St Thomas's Hospital Medical School and qualified MB BS in 1958. He won the Hallett prize in 1960 and became a fellow of the Royal College of Surgeons in 1963. Prior to his consultant appointment, he was a senior registrar at St Bartholomew's Hospital, London, a senior house officer at the Brompton Hospital, London, and a surgical assistant at St Thomas' Hospital. Outside medicine he was interested in silversmithing, pottery and conceptual physics. John Laurence Mercer died on 25 July 2013.