Cowley plant in Oxford. As it turned out, the specialised high-output engines required by the RAF were made by Armstrong Siddeley, Bristol Aeroplane, Napier and Rolls-Royce, all of which employed a high number of sub-contractors. Despite their new factories, protestations by Wolseley Aero Engines (Nuffield) and Alvis were ignored. Their products were not required. Engines were specified by the aircraft's designers. Nuffield did participate after Wood's appointment, providing the Castle Bromwich Factory and promising a thousand Spitfires by June 1940 but, after two years, management was so poor that when June 1940 arrived not one Spitfire had been produced there. Castle Bromwich was withdrawn from Nuffield by Beaverbrook and placed under the wing of Vickers. Implementation The plan had two parts: Development of nine new factories. The government would build and equip the factories. Motor car companies would be asked to gain experience in the making of engine parts so, if war broke out, the new factories could immediately go into full production. Extensions to existing factory complexes to allow either easier switching to aircraft industry capability, or production capacity expansion. Under the plan, there was government funding for the building of these new production facilities, in the form of grants and loans. Key to the plan were the products and plans of Rolls-Royce, whose Merlin engine powered many of the key aircraft being developed by the Air Ministry, as well as Bristol's Hercules engine. Bristol Aeroplane would not allow shadow factories to build complete engines, only components. The exception was Austin. The first motor manufacturers chosen for engine shadows were: Austin, Daimler, Humber (Rootes Securities), Singer, Standard, Rover and Wolseley. In the event Lord Nuffield took Wolseley out of the arrangement and Singer proved to be in serious financial difficulty. The buildings Wood handed the overall project implementation to the Directorate of Air Ministry Factories, appointing Herbert Austin to lead the initiative (most of the facilities to be developed were alongside existing motor vehicle factories), and the technical liaison with the aircraft industry to Charles Bruce-Gardner. He also handed the delivery of the key new factory in Castle Bromwich, that was contracted to deliver 1,000 new Supermarine Spitfires to the RAF by the end of 1940, to Lord Nuffield, though in May 1940 the responsibility had to be taken from Nuffield and given to Vickers. The buildings were sheds up to long lit either by glazed roofs or "north-lit".