Introduced between 1958 and 1962, 200 of this English Electric design were built and were the pride of BR's early diesel fleet, however by the time the last examples were entering service they had already been replaced on top link duties by more powerful types. Nevertheless these locos provided sterling service for over twenty years and were mainly to be found in the north of England as well as Scotland. The class started to be taken out of use in the early 1980's with the last taken out of regular service by 1985.