Calls are growing among MPs for the government to consider the future of Railtrack following the company's latest admission of problems.

Railtrack on Monday claimed major expansions of the network would be under threat unless the government advanced a £1 billion grant. It said that without the money the second phase of the Channel Tunnel Rail Link and the upgrade of the East Coast main line from London to Edinburgh would both have to be scrapped. It said that without the cash it would be £8 billion in debt by 2003.

Railtrack's chief executive, Steve Marshall, said: "We will be avoiding new commitments until we can confirm that our financeability is resolved."

The chairman of the Commons transport sub-committee, Gwyneth Dunwoody, told epxNews that the company should not expect the money without guarantees. "If Railtrack wants the support of the taxpayer to supply the funds then it must come forward with an engineering plan that will demonstrate that bad maintenance and broken rails are a thing of the past," she said.

She also poured doubt on the long term future of Railtrack, saying: "The government must ask the Strategic Rail Authority to consider whether Railtrack should continue in its existing form."

Committee member Brian Donohoe also added his voice to those calling for change. He said: "If they do get it then there must be some kind of government stake or there has to be a very close level of accountability. This situation comes as no surprise when, as a committee, we have seen the very clear degrees of incompetence in Railtrack that has brought this about. Why should we be the ones to bail them out under these circumstances?"

Conservative MP Anne McIntosh accused the government of making the situation worse. "They have behaved very badly by bringing the company in every 10 minutes for rail summits," she said. "The targets that have been set by the regulator are also unrealistic."

McIntosh said that Railtrack must also shoulder some of the blame. "If the money were to be used to bring the maintenance in-house then I think it would be a very good idea. I don't think it would be rewarding the company; no-one wants to see Railtrack go bust. However, everybody would like to see Railtrack put its house in order," she said.