The Halifax was produced in large numbers during the war: of the 10,018 heavy bombers produced in Britain between 1940 and 1944, 4,046 were various models of the Halifax – in excess of 40%. In all, 6,178 Halifaxes were built, the last delivered in April 1945. At the peak, 41 separate factories and dispersed units were involved in production, along with 600 subcontractors and 51,000 employees, with one Halifax completed every hour. The first English Electric-built aircraft was flown from Samlesbury on 15 August 1941.