Roderic Gregory (usually known as ‘Rod’) was born on 29 December 1913, at 63 Braemar Road, Plaistow, London. He was the only child of Alice Jane Gregory (nee Greaves, 1889–1978) and Alfred Gregory (1884–1938). His father was a fitter and turner who, in 1913, was employed by Brunner and Monde (later Imperial Chemical Industries). His mother had worked from the age of 14 making cardboard boxes for chocolates. The factory at which his father worked became involved in the manufacture of munitions early in the First World War. However, safety standards were low and, realizing this, his father soon moved to another local factory making flashlight batteries. His forebodings proved correct as shortly afterwards the entire plant exploded killing many.