The chance of Brexit happening is “50-50” if the prime minister’s withdrawal agreement is rejected by MPs, Brexiteer Liam Fox has said.
The international trade secretary told The Sunday Times that Brexit would only be “100% certain” if MPs support Theresa May’s deal in a crunch vote in January.
Dr Fox said rejecting the deal would be “incendiary” and that MPs must support it as “a matter of honour”.
“Parliament cannot now, with any honour, renege on that result [of the referendum],” he said.
“Were they to do so, I think you would shatter the bond of trust between the electorate and parliament. And I think that would put us into unprecedented territory with unknowable consequences.”
MPs are due to return to the Commons on 7 January and will begin a new debate on Mrs May’s deal on 9 January.
The vote is then expected to take place the following week.
It was first scheduled for before Christmas but was pushed back at short notice when it became clear that the government would suffer a heavy defeat.
If the deal is rejected the country could be heading for a “no-deal” Brexit – and there is also speculation that a second referendum could be triggered.
Jeremy Corbyn has urged the PM to cut short the Christmas break for an earlier vote, accusing her of trying to “run down the clock” and offering MPs a choice between “the devil or the deep blue sea”.
Meanwhile, European Commission chief Jean-Claude Juncker has denied he is trying to keep the UK in the European Union.
EU leaders rejected Mrs May’s appeal for further assurances over the controversial Irish backstop earlier this month – something that could have assuaged the concerns of some MPs.
“It is being insinuated that our aim is to keep the United Kingdom in the EU by all possible means. That is not our intention,” said Mr Juncker.
“All we want is clarity about our future relations. And we respect the result of the referendum,” he told German newspaper Welt am Sonntag.
Mr Juncker said the European Union was poised to start negotiating its future relationship with Britain as soon as MPs back Mrs May’s deal.
He also refused to be drawn on whether a second Brexit referendum could be held if the PM loses the vote, saying: “That is for the British to decide.”