Theresa May will deploy ministers to sell her Brexit deal around the UK on Friday after Tory backbenchers handed her a possible lifeline to get it through Parliament.

Senior Cabinet ministers including Chancellor Philip Hammond and Health Secretary Matt Hancock are among those who will make another late push to garner support for Mrs May’s Withdrawal Agreement ahead of Tuesday’s vote.

They hit the road after MPs tabled an amendment to the meaningful vote on the Withdrawal Agreement that would give MPs some control over the controversial Northern Ireland border backstop, which has been the main sticking point after two years of negotiations.

The alteration would mean Parliament would have to approve a decision to trigger the backstop arrangement or extend the transition period beyond December 2020.

It was tabled by Northern Ireland minister Sir Hugo Swire, Richard Graham and Bob Neill, hours after the Prime Minister indicated Parliament would choose between the two options after the UK formally quits the EU.

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

(PA Graphics)
(PA Graphics)

But it remains to be seen whether it goes far enough to win over enough Tory Brexiteers to get the deal through the Commons.

DUP leader Arlene Foster, whose party opposes Mrs May’s deal, warned that the amendment would not be enough, tweeting: “Domestic legislative tinkering won’t cut it.

“The legally binding international Withdrawal Treaty would remain fundamentally flawed as evidenced by the Attorney General’s legal advice.”

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.

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.

The amendment would add provisions for the Commons to “approve the Government’s proposed approach, including whether or not an extension to the implementation period should be pursued; and parliamentary approval of the commencement of the powers implementing the Northern Ireland backstop”.

Mr Graham, who sits on the Exiting the EU Committee, told the Press Association it had been clear for some time the backstop “was and remains the thing that gives colleagues the most concern”.

He said: “What we are trying to achieve is something that gets a lot of support from colleagues and that the Government, we hope, will take forward because it will make a real difference to the vote.”

Earlier on Thursday, ITV had joined the BBC in cancelling plans to broadcast a televised Brexit debate between the Prime Minister and opposition leader Jeremy Corbyn, after Labour and the Conservatives failed to agree which of the rival offers to accept.

Downing Street Christmas tree
Prime Minster Theresa May switches on the lights on the Downing Street Christmas tree on Thursday, with the help of children from her constituency (Dominic Lipinski/PA)

Both channels had wanted to host the live programme on Sunday evening, two days before the vote, but it now seems unlikely a head-to-head will go ahead.

Mrs May faced calls to postpone Tuesday’s vote, with senior Conservative MP Sir Graham Brady, chairman of the backbench 1922 Committee, saying he would welcome the vote being deferred if no solution could be found to differences within the party over the backstop.

Sir Graham told BBC Two’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.”

(PA Graphics)
(PA Graphics)

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

And former prime minister Tony Blair, asked at a Westminster lunch if Mrs May should pull the December 11 vote, said: “Personally, I don’t see what the point is in going down to a huge defeat.”

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 and “nothing to get excited about”.