Steve Norris, the minister for transport in London, dismissed as 'nonsense' a report that the Government may postpone the legislation until the next session of Parliament.
Mr Norris said the Government still planned to complete the legislation in the overspill period between mid-October, when Parliament resumes after the summer recess, and the next Queen's Speech in early November.
'There are absolutely no plans to rethink British Rail privatisation. It is nonsense. We are looking to the parliamentary overspill period to complete the passage of the Bill,' he said.
This overspill period is the few weeks between the end of the long summer recess and the Queen's Speech, usually in early November, which opens the new session.
However, the Government is considering contingency plans for overturning the vote in the House of Lords, which gave British Rail the right to bid for franchises, as reported yesterday in the Independent on Sunday.
Brian Wilson, a Labour spokesman, accused Mr Norris of 'blustering'. He said: 'With one more push the whole thing can be called off.'
Tory rebels are threatening to defeat the Government, if it attempts to reverse the Lords' vote, when the Bill returns to the Commons.
Mr Wilson added: 'The evidence is overwhelming that the Government is looking for escape hatches. John MacGregor, Transport Secretary, is like a cornered rabbit looking for a hat to jump out of.'
Lord Peyton, a Tory peer and former minister for transport, who is leading the Tory revolt against the Bill in the House of Lords, described the government plans as 'a nightmare . . . absolutely dotty'.
He said: 'If ministers were to announce at the Tory conference they were dropping the plans they would get a standing ovation.'
Lord Peyton said the Bill would produce a system complicated for both operator and passenger, and one very unlikely to work.
The Government has asked parliamentary clerks to examine ways of continuing the Bill in the next session, if necessary; and ministers are considering avoiding defeat by leaving the Lords' amendment unchanged, but inserting a government amendment to force BR to sell off any franchises it wins.
Tory unease about the privatisation of BR is expected to surface at the party conference in October. Many backbenchers fear they could lose their seats if commuters turn against them, and a clutch of motions critical of the Bill is expected to be on the agenda.