John Desmond Cronin was born on 1 March 1916, the son of John Patrick Cronin. He received his medical training at London University where he qualified in 1939. Thereafter he held house officer appointments at St Bartholomew's (1939-1940) and the Royal Free (1941-1942) Hospitals. He joined the Royal Army Medical Corps in 1942 and served as a surgical specialist in Burma, France and Germany until 1946. After the war he was appointed orthopaedic surgeon at the Prince of Wales Hospital from 1947 to 1951 and in 1948 held a similar post at the French Hospital. He was made a Chevalier of the Légion d'Honneur in 1960 and an Officier in 1967. He joined the Labour Party in 1947 and for a time was adviser on industrial injuries to a number of trade unions. In 1950 he became vice-chairman of the North St Pancras Labour Party and was a member of the LCC from 1952 to 1955. He then became Member of Parliament for Loughborough from 1955 until 1979 and was Opposition Whip from 1959 to 1962. He married Cora Mumby-Croft (daughter of Rowland Mumby-Croft) in 1941 and they had a son, Charles and two daughters, Anne and Pauline. On 3 January 1986 he was found dead near his home in Hampshire and it was thought that he might have had a heart attack after falling from his horse.