Official figures have revealed that The Jubilee Line upgrade which was delivered through the public-private partnership blew its budget by £436m, with a final cost of £721m.
The original contract cost for the upgrade which was signed at the end of 2002 was for only £285.3m.
Transport for London said it demonstrates “why it was essential for TfL to acquire Tube Lines and bring upgrade work under the direct control of London Underground, effectively ending the PPP”.
They continued to say “Numerous deadlines, including the contractual deadline of end 2009, were missed, and the improvements were not delivered until after the work came under the direct control of TfL.
“Following the acquisition and transfer of Tube Lines to TfL in June 2010, TfL was able to ensure LU and contractors worked together, instead of through adversarial contractual arrangements, and set out a clear and achievable programme and milestones towards completion of the upgrade, which was delivered in July this year.
“Ending the PPP also means that TfL can plan future upgrade and maintenance work in a way that sees all partners and contractors work together in much more efficient and economic way, saving hundreds of millions of pounds now and in the future.
“This will ensure that the next major upgrade, on the Northern line, will be delivered in a more efficient, economic and also far less disruptive way to Londoners and businesses.”