W.O. Bentley realised his ambition to built the first true all-English sports car with the first prototype Bentley 3 Litre in 1919, though careful testing prior to start of production caused considerable delay and not before 1921 the first car was delivered to customer. The four cylinder engine with four valves per cylinder became renowned for its sturdiness and Bentley fielded works entries in the most severe competitions like the Tourist Trophy and the 24 Hours at Le Mans with considerable success. This boosted sales at the factory and provided the information for constant improvement. In addition to the basic version TT models and Speed models were offered. The Super Sports, of which only 18 were built, was capable of exceeding the magic figure of 100 mph.