Britain’s Brexit minister insists a crucial vote on Prime Minister Theresa May’s Brexit deal would go ahead after a newspaper reported she plans to delay it and make a last-minute dash to Brussels to seek a better offer.

Several pro-Brexit former government ministers on Sunday piled pressure on May to go back to the European Union and renegotiate a deal that has won little support among her own Conservatives and opposition parties.

Ms May’s deal looks set to be rejected by parliament on Tuesday, a decision that would throw plans for Britain’s exit from the EU into turmoil and leave her own political future hanging in the balance.

The Sunday Times reported Ms May was expected to announce on Monday that she was delaying the vote to head to Brussels to make a final appeal to the EU to improve Britain’s exit deal.

“The vote is on Tuesday, that is what we are focused on,” Brexit minister Stephen Barclay told BBC TV on Sunday.

“The risk for those who say simply go back and ask again, the risk is that isn’t necessarily a one way street, the French the Spanish and others will turn round, if we seek to reopen the negotiation, and ask for more,” he added.

Mr Barclay said Britain would enter “uncharted waters” if it loses the vote, but May could stay on as prime minister.

There has been speculation Ms May might use an EU summit on December 13-14 to press for changes to the deal.

The strongest opposition centres around the so-called backstop, an insurance policy designed to prevent a hard border between EU member Ireland and British-ruled Northern Ireland.

Several MPs, including the DUP’s leader in the British parliament, Nigel Dodds, former Brexit minister Dominic Raab and former work and pensions minister Esther McVey, on Sunday called for May to go back to Brussels and seek to renegotiate the deal.

Former foreign secretary Boris Johnson, a leading Brexit campaigner, said losing the vote in parliament would give Ms May a mandate to ask the EU to remove it from the deal.

EU diplomats have said they could consider helping Ms May with “cosmetic” changes to the non-binding political agreement but the legally binding text of the exit deal itself would not be renegotiated.

In an interview in the Mail on Sunday, Ms May told MPs the choice was her deal or the risk of “grave uncertainty” for Britain and the chance of no Brexit, or leaving the EU without a deal.

Ahead of the vote, the EU’s top court will say on Monday whether Britain can unilaterally halt its exit from the EU, due to take place on March 29, 2019.

Ms May said rejecting her deal would also risk the opposition Labour Party getting into power. Labour could seek to take control of the country by calling a vote of no confidence in the government if the PM’s deal is voted down.

Leading pro-Brexit Conservative Jacob Rees-Mogg, who has previously called for a leadership contest, wrote in the Mail on Sunday that Ms May should stand down, whether her deal is defeated in parliament’s House of Commons or she seeks to delay the vote.

But Mr Johnson, a possible successor to Ms May, said she could stay on and go back to the EU to renegotiate the deal if she loses the vote.

“What people want to hear now is not stuff about leadership elections and personalities, what they want to hear is that there a plan to get out of this mess,” he said.