The company became known as D Napier & Son Ltd in 1848 when James Murdoch Napier became a partner in his father’s business. The company produced machines for bullet making, gun-boring and turning for a number of government arsenals, as well as coin-weighing machines for the Bank of England. In 1895 James Napier died leaving the business to be bought from the executors by his son Montague Napier. In 1900 Napier manufactured the first ever production six cylinder car. In 1903 production reached 250 cars, overwhelming the company’s Lambeth factory and production moved to Acton, North West London. In 1905 Napier expanded into marine engines, and the Napier II boat set the world water speed record for a mile at almost 30 knots. On the 29th August 1906 Napier established the old D Napier & Son Limited as a Private Limited Company taking all the shares and holding the position of sole governing director. In 1913, following a dispute with Selwyn Edge, bought Edge's company S. F. Edge distribution and sales company of motor cars, marine engines and tractors with an agreement that Edge would not be involved in motor manufacturing for seven years. Production rose to around 700 cars a year with many supplied to the London Taxi trade. The same year the business became a public company. During the First World War Napier also had a base at Luton Airport used for Flight Development. This site grew and became involved in the development of rocket engines and de-icing systems. Vehicle production continued and 2,000 trucks and ambulances were supplied to the War Office. In 1919 civilian car production re-commenced with a 6 litre six-cylinder car, however, car sales declined and the last cars were made in 1924 and instead the company concentrated on aero engines and Montague Napier died. In 1942 the English Electric Company acquired D Napier & Son. In 1944 Napier designed and supplied diesel engines for use in Royal Navy patrol boats and in 1961 the company was purchased by Rolls Royce although products continued to be produced using the Napier name. The Napier name continued however, the name D Napier & Son finally vanished when the business name was changed to Napier Turbochargers Ltd on 16th December 1974.