William Edward Rootes, 1st Baron Rootes GBE (17 August 1894 – 12 December 1964) was a British motor manufacturer. He opened his first car sales agency in 1913, leading to the global Rootes Group. During the Second World War he supervised the volume manufacture of aircraft and engines, as well as the supply of military motor vehicles and armoured fighting vehicles. He was knighted in 1942 for these services and for organising the reconstruction of bomb-damaged Coventry after its saturation bombing by the Luftwaffe on 14–15 November 1940. In the 1950s, he became a leader of Britain's export drive, and chaired a committee to found the University of Warwick with a vision of academic links with industry.
William (Billy) Rootes was born in Goudhurst, Kent. His father, William, owned a general engineering business in Goudhurst, which included bicycles. William (Snr) attended a motor show organised by Sir David Salomons in Tunbridge Wells in 1895. Billy and his brother Reginald (Reggie) shared their father's interest in things mechanical. In 1905, whilst their parents were out, Billy took Reggie out for a drive in their father's New Orleans motor car. Unfortunately, Billy crashed the car. Billy attended Cranbrook School, and on leaving school in 1909 was apprenticed to the Singer car company. William had moved the family business to Hawkhurst by this time, and expanded into the motor trade. Billy left Singer in 1913 to start his own car agency. He sold all of his first batch of cars within a few months of leaving Singer. The business was moved to Maidstone before the First World War, and the firm worked on the maintenance and repair of aero engines during the war.
William and Reginald were knighted in 1942 and 1946 respectively for their work in setting up shadow factories. William was created a baron in 1959, some five years before such honours ceased to be inheritable under the UK honours system: his eldest son would accordingly become the second Baron Rootes on William's death.