The collapse of the subprime mortgage market in America helped to boost sales at this Hertfordshire company, which specialises in securing, monitoring and maintaining vacant residential and commercial properties. Its services include boarding up, guarding and alarming properties, as well as maintenance. Half of its sales are generated in the United States, but VPS also has operations in Britain, France, Ireland, Germany, Italy and Spain. The company was acquired by TDR Capital in a secondary buyout from Axial European Partners in March 2010 for an undisclosed amount. Thanks to recent acquisitions, the company’s international sales grew 130% a year, from £20m in 2009 to £105.8m in 2011