The future of Railtrack's parent,Railtrack Group, remains unclear after talks between the British Transport Secretary, Mr Stephen Byers, and rail industry chiefs broke up yesterday without agreement. Mr Byers will inform Railtrack in writing on Monday whether the British government is willing to guarantee Railtrack Group's operation of part of the Channel Tunnel Rail Link.

Britain's rail operator was put into administration last Sunday amid growing concern about the company's debts and following the British government's decision not to provide extra subsidies.

Yesterday's crucial talks between Mr Byers and Railtrack's chairman, Mr John Robinson, and chief executive, Mr Steve Marshall, focused on the financial security of Railtrack Group and its interest in the rail link, valued at about £400 million sterling (€640 million).

If Mr Byers guarantees Railtrack Group's rights over the link, it could help retain some value in Railtrack shares - probably about 70p per share - and soften the blow of insolvency for more than 250,000 shareholders.

After the meeting, Mr Robinson said Mr Byers had told him he hoped to respond positively, but Mr Byers has already made it clear that he will not use public funds to rescue shareholders in a private company. Mr Robinson said it was crucial the group retained the rail link - otherwise Railtrack Group's financial solvency would be "imperilled".

Ahead of the talks at the Department of Transport, the German bank, West LB, confirmed it had made a "preliminary approach" to the government outlining its interest in Railtrack.

But it was not clear whether West LB, which bid £18 billion sterling in July for BT's fixed line network, was interested in Railtrack or the not-for-profit firm expected to replace it.

A government spokesman said a "realistic offer" would not be ruled out.