Metronet has asked London Underground for £551m to cover parts of the Tube upgrade but was only givern £121m by the PPP regulator.
Metronet have said that TFL and London Underground have changed the specifications that were originaling outlined in the contracts and have been asking for higher quality of work and more expensive upgrades. The authority for TFL has said that the overspend of the works was because of mismanagement and a failure to control costs by Metronet.
Metronet are not responsible for the day to day running of the London Underground train system and the services and maintenance will carry on as normal.