MINI, Plant In Oxford, Capital Oxfordshire County, South East England, United Kingdom

A shadow factory is a term given to dispersed manufacturing sites in times of war to reduce the risk of disruption due to enemy air-raids and often with the dual purpose of increasing manufacturing capacity.
Production of the Supermarine Spitfire at its parent company's base at Woolston, Southampton was vulnerable to enemy attack as a high profile target and was well within range of Luftwaffe bombers. Indeed on 26 September 1940 this facility was completely destroyed by an enemy bombing raid. Supermarine had already established a plant at Castle Bromwich, this action prompted them to further disperse Spitfire production around the country with many premises being requisitioned by the British Government.
Connected to the Spitfire was production of its equally important Rolls-Royce Merlin engine, Rolls-Royce's main aero engine facility was located at Derby, the need for increased output was met by building new factories in Crewe and Glasgow and using a purpose-built factory of Ford of Britain in Trafford Park Manchester.