Deadline:Livingstone

Stephen Byers and London Underground will find themselves in court unless they hand over key documents over the PPP Tube deals to London's mayor.

Ken Livingstone issued an angry statement on Thursday warning that unless he and transport commissioner Bob Kiley have received details related to the value for money assessments and risk transfer by 4pm on Friday he will take his battle to the High Court.

"We are supposedly being consulted on the final documents on the PPP. But it turns out that at the time the secretary of state was advised to proceed with the PPP, it was impossible to determine whether it represented value for money because such vital matters as the risk transfer to the bidders were then - and for all we know could still be - under negotiation," he said.

"Vital documents on these issues are either being withheld or remain under negotiation, either way rendering the present consultation meaningless."

Livingstone believes there are two possible reasons for the missing details; either London Underground and ministers are withholding information deliberately or they are still negotiating with the bidders which would negate the value for money assessments made by Ernst and Young for Stephen Byers.

London Underground hit back saying they were confident of winning any action brought by the mayor.

"London Transport has complete faith in its processes. We had complete faith in our processes when we went down this road last year and we retain that faith now," said a spokesman for the Tube.

At the mayor's question time on Wednesday, Livingstone told members of the GLA that "no reasonable person" would sign off the deals as they currently stand.

"We are close to the point where I think they [the contracts] are so unreasonable that no reasonable person should sign them," he said.

London's mayor warned that the entire modernisation programme had been removed and the contracts amounted up to little more than maintenance deals.

"We have finished reading the PPP contracts. Virtually the entire modernisation proposals have been deleted from the contracts to bring them down in cost. Apart from the on-going maintenance of the Underground there are virtually no proposals for modernisation of track, signals and trains. Just 15 new trains will be provided through the first seven years of the contracts," Livingstone said.

He then turned his anger on Gordon Brown and the Treasury for going back on promises made to his transport commissioner Bob Kiley.

"The Treasury has ratted on the deal of putting in more money. Treasury input will be no more than in the last 15 years which has historically been a period of under funding," he said.

The capital's mayor added to the transport secretary's woes by accusing him of going back on a promise he made during a TV interview.

Stirring accusations that Byers had mislead television viewers last Sunday, Livingstone claimed the embattled cabinet minister had yet to release all the information on the equity rate of return despite a promise on Newsnight several weeks ago.

The mayor believes the rate is around 35 per cent but the part of the document related to the issue merely has an asterisk in the place of figures.

"This is far from over. We were promised a full and transparent consultation and we haven't got it," said a spokesman for the mayor.

"Opponents will say that legal action will delay things further. Our argument is simple: the deals mean nothing will happen for years thanks to the contract terms so we're delaying nothing."

On Wednesday the government's controversial tube PPP brought additional Westminster worries to Byers when MPs began a special investigation into the reasons why he decided to press ahead with the part-privatisation.

The transport select committee, which has condemned the deal almost in its entirety, held a one-day hearing into the "key factors" behind his decision.

MPs heard from auditors Ernst and Young who concluded the PPP was "value for money" compared with other ways of finding investment cash.