Wikipedia
Metronet Rail was one of two infrastructure companies (the other being Tube Lines Ltd) in a public-private partnership with London Underground.
Metronet was responsible for the maintenance, renewal, and upgrade of the infrastructure on nine London Underground lines from 2003 to 2008. This included track, trains, signals, civil work and stations. From 18 July 2007 to 26 May 2008, the company was in administration and on 27 May 2008, the company responsibilities were transferred back into public ownership under the authority of Transport for London. In June 2009 the National Audit Office estimated that the failure of the Metronet PPP contract cost the taxpayer up to £410m adding that "most of the blame for Metronet's collapse lay with the consortium itself." The administration complete, the joint administrators petitioned the High Court of Justice for the winding-up of the company on 3 November 2009, the petition to be heard on 10 December 2009.
The remaining London Underground lines, ( Jubilee, Northern and Piccadilly) remained under a PPP arrangement with Tube Lines until May 2010 when it was announced that Transport for London would buy out the Tube Lines consortium.