Prime Minister Theresa May has signalled that MPs could be given the power to decide whether the UK goes into a controversial Brexit backstop arrangement regarding the Northern Irish border.

Mrs May indicated Parliament would choose between triggering the backstop or extending a transition period after the UK formally quits the EU.

The move is likely to be seen as a bid to bolster flagging support ahead of a crunch Commons vote on her EU withdrawal deal next Tuesday – a showdown the PM made clear she would not postpone.

Senior Conservative MP Sir Graham Brady, the chairman of the backbench 1922 Committee, said he would welcome the vote being deferred if no solution could be found to differences within the party over the backstop.

Sir Graham told BBC2’s Newsnight: “I think the most important thing is to have clarity about how we might remove ourselves from a backstop … if we were to enter into one in the future.

“It’s having the answer to that question of substance that is most important, not the timing, so if that question can be answered in the course of the next few days then all well and good.

“If it can’t then I certainly would welcome the vote being deferred until such time as we can answer that question.”

Former prime minister Tony Blair said Mrs May was facing the prospect of “hitting a brick wall at speed” next Tuesday, and would be better advised to act as “facilitator” in the search for a Brexit solution which can command the support of a majority of MPs.

He predicted that no consensus would be found in the Commons and the issue would have to be put to a second referendum.

Asked if Mrs May should pull the December 11 vote, Mr Blair said: “Personally, I don’t see what the point is in going down to a huge defeat.”

Chief whip Julian Smith acknowledged he faces an “uphill challenge” to persuade MPs to back Mrs May’s deal, but insisted that “it’s all to play for”.

Speaking to ITV News, Mr Smith insisted there was no “Plan B” ready to be unveiled if the PM’s proposals are voted down.

“There is no plan, no plan for a vote loss, this is the deal, this deal that we are putting on the table, this is the deal that we need to get through Parliament,” he said.

Asked if Mrs May would survive to the end of the month as PM, Mr Smith said: “Confident Theresa May will be the Prime Minister after the meaningful vote and will be the Prime Minister at and after Christmas.”

In some good news for Mrs May, Liberal Democrat MP Stephen Lloyd announced he was resigning the party whip in order to vote in favour of the PM’s deal.

Mrs May told BBC Radio 4’s Today programme: “There will be a choice between, if we get to that point, a choice between going into the backstop and extending the transition period.

“Now, there are pros and cons of both sides of that.

“People have a concern of the backstop, that we could be in it indefinitely.

“But, in the backstop we have no financial obligations, we have no free movement, we have very light level playing field rules with the EU.

“In the implementation period, we still have to negotiate the terms, but there will be concerns about the fact that they would require, I’m sure they would require, some more money to be paid, for example.

“So there would be arguments on different sides.”

Asked if she would be happy for Parliament to adjudicate on whether to go into the backstop or extend implementation, the PM said: “I think people are concerned about the role of the UK in making these decisions.

“And, the obvious, in terms of the UK, is for it to be Parliament that makes these decisions.”

The backstop, intended to prevent the return of a hard border in Northern Ireland, is highly controversial as Brexiteer MPs claim it traps the UK into obeying rules set by Brussels without a say over them.

The Government says it aims to conclude a comprehensive trade deal with the EU before a backstop arrangement would be needed.

Mrs May said that any deal with the EU, such as a Canada-style free trade agreement favoured by some Brexiteers, would also require a backstop arrangement.

POLITICS Brexit(PA Graphics)

Mrs May’s comments came as the Democratic Unionist Party (DUP) insisted it will withdraw support for her Government if the Prime Minister presses ahead with the Brexit deal with the EU.

Asked if the DUP was prepared to precipitate a general election, the party’s Brexit spokesman Sammy Wilson told BBC Radio 4’s Today programme: “If it comes to the point where the Government makes, shows, a determination to implement the Withdrawal Agreement with its damaging terms at present, or some future version of it, which is still equally damaging, we will not be supporting the Government.”

Eastbourne MP Mr Lloyd said in his resignation letter that he had promised his constituents that he would “support the deal the PM brought back from the EU and not back calls for a second referendum”.

He said he would be “keeping my word to my town”, writing: “I appreciate me voting this way and not supporting a People’s Vote, are counter to the Liberal Democrats’ formal position.

“Consequently, I have decided the only honourable thing for me to do is to resign the party whip in Parliament.”

A Downing Street spokeswoman rejected suggestions that the Withdrawal Agreement could be tweaked ahead of next week’s vote to take account of concerns expressed by MPs.

“We have been perfectly clear that the Withdrawal Agreement is agreed and final,” she said. “What they are voting on is what was agreed in the Withdrawal Agreement and the Political Declaration.”

Number 10 sought to play down the Prime Minister’s meeting with a number of Cabinet ministers on Thursday afternoon.

Downing Street said there was not a full Cabinet meeting.

A source told the Press Association that Mrs May was “seeing a few members of Cabinet” but it was “nothing to get excited about”.

Meanwhile, The EU’s chief Brexit negotiator Michel Barnier reiterated that the agreement with Mrs May was the only deal on offer.

In a speech at the European Committee of the Regions, he said: “I must say once again, today, calmly and clearly – it is the only and the best possible agreement.”

On the issue of the Irish backstop, Mr Barnier said: “It is a legally operational form of insurance that will ensure that we never see the return of a hard border, that we have north-south co-operation on the island of Ireland and that we protect the integrity of the single market.

“The backstop is not there in order to be used, necessarily. We will do our utmost to avoid ever having to use it.”

Under the Withdrawal Agreement, the backstop would be introduced if a trade deal had not been agreed by both sides by the time the transition period ends in December 2020.

However, the transition period could be extended for a maximum of two more years.

All MPs who are members of the Privy Council have been invited to briefings on Thursday by the Civil Contingencies Secretariat on preparations for Brexit, said Number 10.

Also invited for briefing were the first ministers of Scotland and Wales and representatives of the Northern Irish parties.

And, a European Court of Justice ruling on the reversibility of Article 50 will take place the day before MPs vote on Mrs May’s Brexit deal, the court has announced.

Elsewhere, a YouGov poll of more than 20,000 Britons suggested just two parliamentary constituencies would pick the Prime Minister’s Brexit deal above staying in the EU or leaving with no deal.

People were asked to rank her deal, no deal and remain in order of preference, but only two constituencies put it in first place: Tory-held Broxbourne and Christchurch.

Mrs May’s deal was supported by 27% of those surveyed, while remain had 46% and is first preference in 600 constituencies, according to the poll carried out over the past week.

But no deal was found to be first choice in 30 seats, with 27% supporting it.