D0280 Falcon was a single prototype diesel-electric locomotive, built for British Railways in 1961. It was one of a series of three prototypes: Falcon, DP2 and Lion, eventually leading to the Class 47 and Class 50. A requirement was expressed by the BTC at a meeting on 15 January 1960 for new Type 4 designs of Co-Co arrangement, which would be lighter than the earlier 1Co-Co1 locomotives such as the Peak classes, produced under the .