The British Rail Class 101 diesel multiple units were built by Metro-Cammell at Washwood Heath in Birmingham from 1956 to 1959, following construction of a series of prototype units. This class proved to be one of the most successful and longest-lived of BR's First Generation DMUs, second in age only to the Class 121, with the final five units being withdrawn on 24 December 2003. The oldest set was, by then, just over 47 years old.