W.O. Bentley showed the first factory-built Supercharged Bentley 4.5 Litre at the London Olympia Motor Show in the autumn of 1929. The first 25 supercharged cars received chassis numbers beginning with SM; these had smooth-cased 'blowers.' The next 25 chassis numbers, beginning with MS, had ribbed blowers to aid cooling. This car still has its original supercharger cover, designed to keep the outside carburetors warm and prevent icing up in cold weather. This motor car is considered by many people in the Bentley community to be the most original of the 50 supercharged 4.5 Litres produced by the factory. Its original Rexine-covered body shows the original blue paintwork that was uncovered during its recent conservation. It was first sold to Mr. G. B. Sanderson, fitted with rare Bosch headlamps and a larger-than-standard 25-gallon fuel tank. In 1948 it passed to noted collector Raymond Erith, who summarized the car as 'quite the nicest car' he had ever owned. Dick Stitt of Chicago took ownership in 1955 and maintained its originality for the next 33 years. Its current owner acquired the car in 2011. 2019 was the first time it had been shown at the Pebble Beach Concours d'Elegance.