1937 - Bristol 'Blenheim IV L8756', Royal Air Force Museum, Hendon, 10 September 2015 1. The Blenheim light bomber was developed from a fast civil airliner. It entered RAF service in 1937, but was soon outstripped by monoplane fighters such the Messerschmitt Me-109 with heavy losses. 4422 Blenheims were built in various versions but only one original survives, in Finland. Several Canadian built Bristol Fairchild Bolingbroke Mark IV-T trainers now represent Blenheims. This is 10001, built in 1942.