LMS No. 10000 and 10001 were the first mainline diesel locomotives built in Great Britain. They were built in association with English Electric by the London, Midland and Scottish Railway at its Derby Works, using an English Electric 1600 hp diesel engine, generator and electrics.
The locomotives operated singly and in multiple on the West Coast Main line and hauled many of the premier named expresses of the day including the Irish Mail, Lakes Express, Manxman, Mancunian, Mid-Day Scot, Coronation Scot, Royal Scot, and Ulster Express, plus outer suburban services from Euston to Watford Junction and Hemel Hempstead.
Under British Railways, the locomotives became British Railways Class D16/1; they were initially operated primarily on mainline express passenger services on former LMS lines, both in single and in multiple. In 1953, they were transferred to the Southern Region for comparison with O. Bulleid's British Rail Class D16/2 diesel locomotives.
Both locos were withdrawn and scrapped in the 1960s.