The Mayor of London, Boris Johnson, has told MPs that there could be further disruption on London Underground's Jubilee Line due to difficulties with Tube Lines, who run the maintenance of some of the Underground lines.
He was giving evidence to the Transport Committee on 9 December 2009 as part of an ongoing inquiry into the role of PPP (public-private partnership) in the maintenance of London Underground.
Under PPP, London Underground is still publicly owned, but private companies were appointed to maintain and upgrade the infrastructure and support services.
Originally two PPP companies - Metronet and Tube Lines - were appointed for the maintenance roles, although Metronet went into administration in 2008, with its work going back into public ownership through TfL.
A report during the summer by the National Audit Office revealed that the collapse of Metronet cost the taxpayer up to £410m.
Mr Johnson said that Metronet was a "poorly conceived system" that had not operated in the best interests of Londoners.
Later in the session, PPP was criticised by representatives from the two main rail trade unions, the RMT and ASLEF.
Speaking for the RMT, Bob Crow said that too much focus had been given to station modernisation, rather than improving service quality.
Transport Minister Sadiq Khan rounded off the session by telling the committee that he thought that PPP had proved good value to customers, as it had led to the improvement of services on the Underground.
However he said that he was not an "ideologue" and said that the decision to keep Metronet's work under public ownership was proof that he was not "blinded to the concept" of PPP.