 The design of a full-size Transistor Computer was subsequently adopted by the Manchester firm of Metropolitan-Vickers, who changed all the circuits to use more reliable junction transistors.The production version was known as the Metrovick 950 and was built from 1956 to the extent of six or seven machines, which were "used commercially within the company" or "mainly for internal use".During the mid-1950s a series of similar machines appeared.