The Jubilee Line has been shutting on weekends since 2007
The government's part-privatisation of the London Underground was "flawed" and further delays for maintenance work are unacceptable, a group of MPs has said.
Despite 100 weekend Jubilee Line closures, private company Tube Lines' work will be completed 10 months late, the Commons Transport Committee said.
Tube Lines and the now-defunct Metronet were given 30-year contracts to maintain the Underground in 2003.
Transport for London wants a government review of public-private partnerships.
Metronet went into administration in 2007 and London Underground (LU) took over its responsibilities in May 2008, with Tube Lines continuing its work.
"The ongoing disruption caused to people who rely on the Jubilee line to go about their daily lives, and the cost to businesses, is unacceptable," the MPs said.
The committee's chairman Louise Ellman said: "We stand by our previous conclusions that the public-private partnership (PPP) is fundamentally flawed.
"Although the performance of Tube Lines has in some cases been exemplary, its failure to upgrade the Jubilee Line on time marred its overall record badly."
Metronet went into administration in July 2007
The report went on: "We are deeply concerned at the increasingly antagonistic relationship, stoked by the mayor (of London, Boris Johnson), between Transport for London, and LU on one side, and Tube Lines on the other.
"Relations between the parties have deteriorated further over the past year."
"Some 20 months following the demise of Metronet, the government is no nearer to being able to demonstrate that the PPP provides value for money for the taxpayer."
The mayor said in a statement: "This is the latest in a litany of damning verdicts on the PPP, and the failure of Tube Lines to deliver for London.
"This is a system that has wasted hundreds of millions of pounds of public money, yet the government continues to wash its hands of the mess it has created.
"The government must urgently review the PPP to ensure that Londoners get the vital upgrades they were promised, in full, on time and in a way that represents value for money."
Tube Lines said the report acknowledged that London Underground's work was up to one third more expensive than Tube Lines.
"As we have always said, it is regrettable that the deadline for completing the Jubilee line upgrade was missed, but we are working hard to deliver the project by the end of May so that passengers can benefit from faster, more reliable services.
"Important lessons have been learnt and are being incorporated by us into the Northern line upgrade to speed up work, lower costs and minimise disruption."