Theresa May warned another Brexit defeat in the Commons is 'inevitable'

The prime minister is preparing for a huge week in Westminster, with the withdrawal agreement she struck with Brussels set to go before parliament yet again.

She has been trying to secure legally binding changes to the unpopular backstop to convince MPs that the UK cannot be tied indefinitely to EU rules against its wishes, which she hopes would be enough to get the deal through.

But the likelihood of that happening appears remote as the clock continues to tick down, and further doubt has been cast over her chances by sceptical Brexiteers who she has been trying to win over.

Steve Baker, deputy chairman of the pro-Brexit Tory European Research Group, and DUP deputy leader Nigel Dodds have described the situation as "grim".

In a joint article for The Sunday Telegraph, the pair said: "An unchanged withdrawal agreement will be defeated firmly by a sizeable proportion of Conservatives and the DUP if it is again presented to the Commons."

It had been speculated that Mrs May could try to secure a third meaningful vote if she loses by less than 50 on Tuesday, but a loss as predicted by Mr Baker and Mr Dodds would make that prospect unlikely.

Should she indeed lose, the prime minister would be primed to give MPs the chance to vote against departing the EU without a deal and to request an extension of Article 50, which would delay the current 29 March leaving date.

Both prospects have some cross-party support, with several cabinet ministers having indicated that they would be prepared to support a motion to prevent no deal.

Mr Baker and Mr Dodds warned any delay to Brexit would do "incalculable" damage to public trust in politics.

"For some, democracy would be effectively dead," they said.

There have also been reports that some in the cabinet have told Mrs May she may have more luck getting her deal approved by parliament if she agrees to stand down by June.

She has previously pledged not to lead the Conservatives into the next general election, but that is not until 2022.

Meanwhile, her Brexit secretary Steve Barclay has become embroiled in an acrimonious Twitter exchange with EU chief negotiator Michel Barnier.

As officials on both sides continued to discuss the backstop stalemate in Brussels, Mr Barclay accused the bloc of trying to "rerun old arguments" as the two men rowed online.

It came amid a renewed warning from Sinn Fein that the backstop - an insurance policy designed to prevent post-Brexit physical checks on the Irish border - must not be removed from the withdrawal agreement.

Party president Mary Lou McDonald said the divorce should not wreck the Irish economy or the Good Friday Agreement and urged the Irish government to "stay strong" on the issue.

Regarding the British government, she said: "We see indecision and a reckless approach from that government with absolute indifference to Ireland or Irish interests.

"Michel Barnier's position is consistent with ours. If Britain wishes to Brexit who are we to stop them?

"But they won't take Northern Ireland with them and they are not going to wreck the Irish economy and upend our peace process. That's the bottom line."

In the seemingly unlikely event that Mrs May does get her deal over the line, it has been reported that an RAF plane is on standby to fly her to Brussels to clinch it.

But if she fails, the vote to prevent a no-deal is set to go ahead on Wednesday.

Sky News