British shadow factories British shadow factories were a plan developed by the British Government to implement additional manufacturing capacity for the British aircraft industry , in the buildup to World War II . Developed by the Air Ministry under the internal project name of the Shadow Scheme , the project was created by Sir Kingsley Wood and headed by Herbert Austin . Background . Up until 1936 , the Air Ministry had been headed by Lord Swinton , who at that point had been forced to resign his position by Prime Minister Neville Chamberlain due to a lack of progress in re - arming the Royal Air Force . Swinton ' s civil servants approached their new boss , Sir Kingsley Wood , and showed him a series of informal questions that they had asked since 1935 on the subject , such as those posed to Morris Motors with regard to aircraft engine production capability at their Cowley plant in Oxford . Wood ' s immediate response was to put forward a plan which would enable the trebling of aircraft production and manning . Implementation . The plan had two parts : Underneath 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 . 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 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 Spitfire s to the RAF by the end of 1940 , to Lord Nuffield . As the scheme progressed , and after the death of Austin in 1941 , the Directorate of Air Ministry Factories , under the auspices of the Ministry of Aircraft Production ( MAP ) gradually took charge of the construction of the buildings required for aircraft production . In early 1943 the functions of the directorate of Air Ministry Factories were transferred to the Ministry of Works . Follow on initiatives . The shadow factory proposals and implementation , particularly its rigidity when bombed , meant that that other key areas of military production prepared their own shadow factory plans : London Aircraft Production Group . In parallel with the Shadow Factory scheme , the London Aircraft Production Group ( LAPG ) was formed in 1940 by combining management of factories and workshops of Chrysler , Duple , Express Motor & Bodyworks Limited , Park Royal Coachworks and London Transport . The major activity of the group was the production of Handley Page Halifax bombers for the RAF , ammunition , gun parts , armoured vehicles and spare parts for vehicles . The group was led by London Transport from their works at Chiswick and later at Leavesden near Watford , which had a large purpose - built factory and airfield for production , assembly and flight testing of completed Halifax bombers . Due to the high priority placed on aircraft production , large numbers of workers were drafted with little experience or training in aircraft production , with over half the workforce eventually being female . At its peak the LAPG included 41 factories or sites , 600 sub - contractors and 51 , 000 employees , producing one aircraft an hour . The first Halifax from the LAPG was delivered in 1941 and the last , named " London Pride " , in April 1945 . National Archive catalogue entries . Information concerning the Shadow Factory plan and Shadow Factories can be found among the following records and descriptive series list code headings held by The National Archives . For the full set of references ( including German shadow factories ) see the Catalogue below :