the british rail class 101 diesel multiple units were built by metro-cammell at washwood heath in birmingham from 1956 to 1959, following the construction of a series of prototype units. this class proved to be the most successful and longest-lived of all br's "first generation" dmus, with the final five units being withdrawn on 24 december 2003. the oldest set was, by then, just over 47 years old.