The British Rail Class 17 (also known as the Clayton Type 1) was a class of 117 Bo-Bo diesel-electric locomotives built 1962–1965 by Clayton Equipment Company and their sub-contractor Beyer, Peacock & Co., on behalf of British Railways (BR).

During the 1950s and 1960s BR procured a wide range of Type 1 diesel locomotives, many of them under the Pilot Scheme. However, several officials felt that the single-cabbed arrangement used by the majority of Type 1s presented drivers with visibility difficulties in the 'less convenient' direction. BR therefore approached several manufacturers to seek a new locomotive that had a centre cab and low bonnets to maximise visibility. Clayton were selected to produce their proposed locomotive as the Class 17. Its low engine covers required the use of a pair of Paxman 6ZHXL six-cylinder horizontal engines, which had been intended for powering railcars; it was a somewhat unorthodox arrangement for the era.

Production of the Class 17 was undertaken between 1962 and 1965, with the locomotives being assigned to the north of Britain and the Scottish Region. Early on it was determined that the locomotive was not suited to heavy freight trains, and they quickly acquired a reputation for unreliability largely due to the engines, which continued to deliver poor performance even after extensive modifications. The Class 17 proved to be one of the least successful of the Type 1s. Withdrawals took place from the late 1960s to 1971, some locomotives having a working life of less than five years. Several were sold to industrial users; only one example has been preserved.