Millbrook, the Bedfordshire automotive testing and engineering centre, has been sold off by its venture capitalist owner for £122 million.

The business was acquired in 2013 from General Motors by Rutland Partners, and now three years on has netted Rutland a return of more than six times its initial investment through a sale to Spectris, a stock market listed instrumentation and controls company.

Millbrook, established in 1969, is one of Europe’s leading test, validation and engineering service providers for the automotive, transport, tyre, petrochemical, security and defence markets.

The business owns a 665-acre site offering extensive test and validation facilities which complement over 45 miles of on and off road test tracks with a variety of surfaces, features and terrains.

Millbrook also acquired Test World in Finland in 2015, a winter vehicle and tyre testing business with a range of winter tracks and indoor facilities enabling all year around testing within the Arctic Circle.

Rutland said under its ownership the business has been transformed from a General Motors dependent company to one that has a broad base of UK and international clients and test and validation services.

Millbrook will become part of the Test and Measurement Division of Spectris and complement a number of its’ existing businesses. Alex Burns and the majority of the senior management team of Millbrook will remain with the business and help to grow Spectris in its target markets.