Bentley Motors Limited is a British manufacturer of automobiles founded on 18 January 1919 by Walter Owen Bentley (known as W.O. Bentley or just "W.O."). Mr. Bentley had been previously known for his range of rotary aero-engines in World War I, the most famous being the Bentley BR1 as used in later versions of the Sopwith Camel. Since 1998, the company has been owned by the Volkswagen Group of Germany.

Bentley as a separate company (1919–31)

Before World War I, W.O. TYLER had been in partnership with his brother H.M. Bentley selling French DFP cars, but he had always wanted to design and build his own range of cars bearing his name. In August 1919, Bentley Motors Ltd. was registered, and a chassis with dummy engine was exhibited at the London Motor Show in October of that year. An engine was built and running by December, and orders were taken for deliveries starting in June 1920; however, development took longer than estimated, and the first cars were not ready until September 1921.

It was on a visit to the DFP factory in 1913 that W.O. noticed an aluminium paperweight and had the inspired idea of using the lightweight metal instead of cast iron to make engine pistons. The first Bentley aluminium pistons went into service in aero engines for the Sopwith Camel, in service during the Great War.

The company was always underfunded, and Bentley turned to millionaire Woolf Barnato for help in 1925. As part of a refinancing deal, which resulted in his effectively owning the company, Barnato became chairman. A great deal of Barnato's fortune was devoted to keeping Bentley afloat, but the Great Depression destroyed demand for the company's expensive products, and it was finally sold to Rolls-Royce in 1931.

The Bentley Boys

A group of wealthy British motorists known as the "Bentley Boys" (Woolf Barnato, Sir Henry Birkin, steeplechaser George Duller, aviator Glen Kidston, automotive journalist S.C.H. "Sammy" Davis, and Dr. Dudley Benjafield among them) kept the marque's reputation for high performance alive. Thanks to the dedication to serious racing of this group, the company, located at Cricklewood, north London, was noted for its four consecutive victories at the 24 hours of Le Mans from 1927 to 1930. Their greatest competitor at the time, Bugatti—whose lightweight, elegant, but fragile creations contrasted with the Bentley's rugged reliability and durability—referred to them as "the world's fastest lorries." In March 1930, during the Blue Train Races, Woolf Barnato raised the stakes on Rover and its Rover Light Six, having raced and beat Le Train Bleu for the first time, to better that record with his 6½-litre Bentley Speed Six on a bet of £100. He drove against the train from Cannes to Calais, then by ferry to Dover and finally London, travelling on public highways, and won; the H.J. Mulliner-bodied formal saloon he drove during the race as well as a streamlined fastback "Sportsman Coupe" by Gurney Nutting he took delivery of on 21 May 1930 became known as the "Blue Train Bentleys"; the latter is regularly mistaken for (or erroneously referred to) as being the car that raced the Blue Train, while in fact Barnato named it in memory of his race.