Template:List of Siddeley-Deasy Models Siddeley-Deasy (Deasy Motor Company from 1906 to 1912) was a British automobile company based in Coventry in the early 20th century. It was founded by H.H.P. Deasy in the factory that had previously been used to manufacture Iden cars. It changed its name from Deasy to Siddeley-Deasy when J D Siddeley joined the company from Wolseley and Deasy left following disagreement with his Chief Engineer. It merged with Armstrong-Whitworth who had been a suppier of castings to it in 1917 to form Armstrong Siddeley.
Siddeley-Deasy grew rapidly using Rover chassis and Daimler and Aster engines. During World War I, Siddeley-Deasy grew to have 5,000 workers producing ambulances and aircraft engines. They were one of six companies to produce the Royal Aircraft Factory R.E.8 aircraft from 1916.