sentences:  On 2 December 1987, as part of the privatisation of the National Bus Company, United was sold to Caldaire Holdings who had earlier purchased West Riding Automobile Company.In 1990, the Cleveland and Middlesbrough operations were separated and renamed Tees & District, with the Stockton-on-Tees depot operating as TMS (Teesside Motor Services).In 1992, United was sold to the Westcourt Group.