Castle was a British marque produced by the Castle Motor Co. Ltd, based in Kidderminster, Worcestershire. The company was owned by brothers Stanley and Loughton Goodwin, who had manufactured shells, gun carriage hubs, and aero-engine components during the First World War. Like many other manufacturers of the period, the Goodwins sought to meet postwar demand for affordable motoring, choosing to build a three-wheeler with a single rear wheel. Their ambition…