The Prime Minister is being warned she will have to resign should her crunch Brexit vote end in disaster next week, it has emerged.
Several Cabinet ministers have warned her she is heading for a heavy defeat and urged her to seek fresh concessions from Brussels.
They fear if Mrs May goes ahead with Tuesday's vote and loses by a large margin it will prove fatal for her leadership – and open the door to a softer 'Norway-style' Brexit.
Theresa May (pictured above) will decide on Monday whether to pull the crunch Brexit vote amid intense pressure to push for a delay
Last night it was claimed the PM had been warned by several Brexit-backing aides that they are prepared to resign on Tuesday unless there are major changes to her deal.
Mike Wood, the parliamentary private secretary to Trade Secretary Liam Fox, told the Guardian he would quit and join leave-supporting backbenchers unless changes were made.
It is understood that other junior ministers have made similar representations and more were considering their positions.
Eurosceptic Iain Duncan Smith cautioned against Mrs May and her Cabinet deciding to 'brazen it out', saying such an approach would be a 'disaster'.
'How the PM responds after the vote matters more than anything else she has done,' he told the Daily Telegraph.
'I believe that if the response is, 'we've lost but we will do this all over again' it will become a leadership issue.
'I don't want it to be. If she and the Cabinet decide to brazen it out and simply say [a defeat of] anything under 200 is not as big as you think, then that would be a disaster.'
Julian Smith (pictured above) is set to present the Prime Minister with his final count of the number of Tory MPs on whose support she can rely
The paper reported Cabinet ministers have also warned Mrs May she would have to stand down if the deal is defeated and she fails to secure better terms from the European Union.
Last night Amber Rudd became the first Cabinet minister to openly discuss an alternative plan to Mrs May's deal.
The Work and Pensions Secretary told The Times a Norway-style arrangement 'seems plausible not just in terms of the country but in terms of where the MPs are'. A Norway option would keep Britain tied to most EU laws and rules, including free movement and vast annual contributions.
As many as ten senior ministers have privately discussed backing the option. However, one minister described it as 'absolutely horrendous', adding: 'It would split the party for a generation.
'It would also be the biggest betrayal of the British people. We're in real danger now.'
There were also signs last night that Labour is seeking to join forces with rebel Tories and the DUP to force Mrs May's resignation in a no-confidence vote if her Brexit plan is heavily defeated.
In public, Downing Street continued to insist yesterday that the vote on the withdrawal agreement would go ahead as planned.
Leader of the Commons Andrea Leadsom (pictured above) is also understood to be open to the idea of pulling the vote if there is a clear plan about what to do next
But privately aides acknowledged the Prime Minister would 'take stock' over the weekend at her country retreat of Chequers before reaching a decision.
A final media blitz is planned for the next 48 hours as Tory whips canvass MPs on their intentions. Mrs May will then sit down with her inner circle on Monday to make the call. At the meeting, Chief Whip Julian Smith will present her with his final count of the number of Tory MPs on whose support she can rely. In recent weeks more than 100 Tory MPs have signalled their opposition.
One Whitehall source said trying to convince rebels to fall in line was like 'shouting out of a window'. Last night, one Cabinet source said: 'If we're heading for three figures defeat then why go ahead with it?'
An amendment designed to limit the UK's stay in the Northern Ireland backstop appeared dead on arrival after it was blasted by the Democratic Unionist Party – which props up the Tories in the Commons – and Eurosceptics.
A poll also revealed that despite the chaos in Westminster, the parties are running neck and neck among the public. Both Labour and the Conservatives are on 38 per cent, according to the survey by Ipsos Mori.
Arlene Foster (pictured above) has said that 'domestic legislative tinkering won't cut it'
May loyalists are split over what the Prime Minister should do next. Some argue that pulling the vote now and seeking concessions from Brussels at a summit next Thursday – or trying to find a legislative route to satisfy MPs – is her only hope of getting the deal through.
Liz Truss, pudding on the style...
Much like Brexit, black pudding has its devoted fans – but others can't stomach it.
Cabinet minister Liz Truss managed to combine both yesterday with a visit to a butchery.
Liz Truss (pictured above) tries her hand at making black puddings
After posing with a black pudding, she claimed Theresa May's EU withdrawal agreement would give British foodmakers the chance to sell more overseas.
'There's a lot of demand for fantastic British products,' said the Chief Secretary to the Treasury on a visit to the Fruit Pig Company in Wisbech, Cambridgeshire.
But others say any attempt to reopen the deal would be a 'world of pain' and immediately prompt Spain, France and other countries to demand concessions on issues such as Gibraltar and fishing. Last night one senior Tory warned Eurosceptics that not voting for the deal would 'almost certainly' mean leaving on softer terms. 'Eventually you have to stare down the barrel,' said the source. 'There is no Parliamentary manoeuvre which hardens the options that we have now. They are going to have to choose.'
Leader of the Commons Andrea Leadsom is also understood to be open to the idea of pulling the vote if there is a clear plan about what to do next. Hardline Eurosceptics argue a huge defeat would send a signal to the EU that they would need to compromise.
The amendment, proposed by Tory loyalists, would give MPs a vote in 2020 over whether to enter the backstop or extend the transition period – and place a 'duty' on the government to have a workable alternative within a year. But backbench Tory Peter Bone told the BBC the amendment was 'absolutely meaningless'. He said: 'It's got no binding force.'
DUP Leader Arlene Foster said: 'Domestic legislative tinkering won't cut it.' Last night US vice president Mike Pence spoke of a 'strong partnership' after discussions about Brexit with Foreign Secretary Jeremy Hunt.
It appeared to boost the chance of a UK-US deal after Donald Trump last week indicated the EU deal would make it hard to achieve.