Modelled on the
Milford Proving Ground operated by
General Motors (GM) in
Michigan, Millbrook was stated in 1968 by the GM subsidiary
Bedford before passing over to
Vauxhall. Due to the geographical needs of a full testing centre, including both hills and flat land, the traditional choice of a former
Royal Air Force airfield was ruled out and many sites around the UK were surveyed before the location at
Millbrook was decided upon, especially due to having the benefit of being close to Vauxhall's production site at
Luton. Construction of the Proving Ground began in 1968, and once the facility opened in 1970 it acted as the testing site for many European GM models from, among others, the Vauxhall and Bedford companies. With Bedford withdrawing from the bus and truck markets in December 1986, Millbrook was put up for sale by GM. In 1988 the site was transferred to a new company, Millbrook Proving Ground Limited as part of
Lotus and offered its facilities to non-GM companies. With the sale of Lotus in 1993 Millbrook was transferred to GM Holdings UK Limited, as an independently managed company which diversified into all aspects of vehicle testing including
emission control. In September 2016 it was sold to
Spectris. In December 2020 it was announced that Millbrook would be divested from the Spectris portfolio of companies and acquired by UTAC CERAM for £133 million. The divestment was completed on the 2 February 2021. ==Current facilities==