John Charles Leedham-Green was born in Birmingham on 30 October 1902, eldest son of Charles Albert Leedham-Green FRCS (1867-1931), sometime Professor of Surgery at Birmingham University, and his wife, Ethel, née Lees. He was educated at Rugby School and Balliol College, Oxford, where he read chemist

James Llewellin Digby Roberts was born on 15 July 1912 at Kalimpong, India, where his father was a medical missionary. His early years were spent in India, where a favourite family pastime was butterfly hunting on horseback: the superb family collection, which his father initiated, was to become a l