LONDON/BELFAST (Reuters) - Prime Minister Theresa May began a tour of the United Kingdom to drum up support for her Brexit divorce deal with the European Union, while her deputy said on Tuesday parliament might reject it if asked to vote on it now.

FILE PHOTO: Britain's Prime Minister Theresa May makes a statement in the House of Commons, London, Britain November 26, 2018. Parliament TV handout via REUTERS

May has warned skeptical lawmakers that if they reject the deal the world’s fifth largest economy will either leave without an agreement or Brexit could be delayed or even reversed. The vote in parliament is scheduled for Dec. 11.

Amid demands from British lawmakers for May to seek a better deal from the EU, a step Brussels has said it will not countenance, her de-facto deputy David Lidington told Sky News: “If the vote were today, it would be a difficult one to win, but I think that we have time between now and (Dec. 11) to make the case.”

In a separate interview with the BBC, Lidington, the cabinet office minister, said it was “wishful thinking” on the part of some lawmakers that the EU would offer an alternative plan.

“There’s no plan B because the European Union itself is saying the deal that is on the table is the one that we have had to compromise over,” he said.

May sealed a deal with EU leaders on Sunday that would see Britain leave the bloc on March 29 with continued close ties, but now faces an uphill struggle to get it approved by a divided parliament where lawmakers of all parties and on both sides of the Brexit debate have criticized it.

May traveled to Northern Ireland and Wales on Tuesday as part of a tour aimed at rallying support for the deal.

The head of the Northern Irish party which props up her minority government but opposes May’s Brexit agreement said the prime minister was “wasting time” touring instead of fighting for a new deal.

“The prime minister has given up, she is saying this is where we are and we just have to accept that,” Democratic Unionist Party leader Arlene Foster told the BBC.

“But I haven’t given up. I believe in a better way forward.”

DOOMED DEAL?

May faced further censure on Brexit from the United States, where President Donald Trump said the EU got a good deal that may make trade between Washington and London more difficult.

“I think we have to take a look seriously whether or not the UK is allowed to trade,” Trump said. “Because right now if you look at the deal, they may not be able to trade with us ... And that wouldn’t be a good thing. I don’t think they meant that.”

May rebutted the comments, saying a trade deal was possible and that work towards it was making good progress.

Such is the pressure on her leadership that The Times newspaper reported some Brexit-supporting lawmakers in May’s Conservative Party were demanding that she set out when she will quit as a condition for supporting the deal.

The Bank of England and the government will deliver their assessments of the economic impact of Brexit on Wednesday.

May has 314 active Conservative lawmakers in the 650-seat House of Commons and would need around 320 votes to ratify the deal.

Even one of her allies, former defense secretary Michael Fallon, said he could not support it and she should return to Brussels to secure a better agreement.

“My fear is that this deal gives us the worst of all worlds. No guarantee of smooth trade in the future and no ability to reduce the tariffs that we need to conclude trade deals with the rest of the world,” Fallon told BBC radio.

Amid such uncertainty, some lawmakers are calling for Britain’s exit to be delayed or even canceled.

Europe’s top court said on Tuesday it would decide “quickly” whether Britain can unilaterally reverse its decision to leave the EU, a ruling supporters of membership hope could lead to a second referendum and ultimately stop Brexit.