• The Siddeley-Deasy Motor Car Co Ltd

In 1905 John D Siddeley, founder of Siddeley Autocar Co (est. 1902), became London sales manager of The Wolseley Tool & Motor Car Co which had purchased the goodwill and patent rights of his Siddeley car. He resigned from Wolseley in 1909 and became general manager of The Deasy Motor Car Manufacturing Co Ltd (est. 1903), Coventry. Deasy, the company’s founder had left in 1908 and in 1912 the company's name changed to The Siddeley-Deasy Motor Car Co Ltd. Siddeley-Deasy grew, building cars using Rover chassis and Daimler and Aster engines. They also established a separate motor car brand called Stoneleigh. During the First World War, Siddeley-Deasy produced ambulances and aircraft engines, including the Puma, and, from 1916, Royal Aircraft Factory R.E.8 aircraft. In 1917 three Royal Aircraft Factory staff, Major F M Green, Sam Heron and John Lloyd, joined Siddeley-Deasy when the factory’s design function was dismantled, bringing with them designs for a new radial engine. Engine designer Heron left after disagreements with Siddeley, but Green became chief engineer and Lloyd chief aircraft designer and both remained with both Siddeley Deasy and its successor. During 1917-18 the team led by Lloyd designed three aircraft, one of which, the Siskin, became well known. Heron was later replaced by F R Smith who developed an engine that eventually became the Armstrong Siddeley Jaguar. After the war orders diminished and in 1919 Siddeley suggested a merger with Sir W G Armstrong Whitworth & Co Ltd’s motor car department. Armstrong-Whitworth had been a supplier of Siddeley-Deasy engine castings and had itself made aircraft though it had decided to abandon aircraft manufacture by 1919. Armstrong Whitworth acquired a controlling interest in The Siddeley-Deasy Motor Car Co Ltd and changed its name to The Armstrong Siddeley Co Ltd. In 1919 W G Armstrong Whitworth Development Co, Newcastle upon Tyne, formed a subsidiary, Armstrong Siddeley Motors Ltd, to take over the car and aircraft businesses of both Armstrong Whitworth and Siddeley-Deasy Motor Car Co at Parkside works Coventry. John Siddeley became chair of the new company.