In 1955, Metropolitan Cammell produced its first lightweight diesel multiple units, the prototypes of what were to become British Rail's most successful and longest-lived First Generation DMU type, the Class 101.

The seven London Midland Region sets (formed DMBS + DTCL) were used on the Bury-Bacup line services, while the other sets (formed DMBS + DTSL) were all allocated to the Eastern Region.

A unit consisting of 79066 and 79282 worked the last passenger service on the Aldeburgh Branch Line in 1966.

[1] They proved to be very successful, but with line closures continuing through the 1960s, including many in East Anglia where the type was first used, their non-standard coupling arrangements left them prone to early withdrawal, which took place during 1967–1969.

They were used at the Railway Technical Centre in Derby as Laboratory 21: Plasma Torch Research.