Theresa May has urged Tory MPs not to submit letters of no confidence as she warned a ballot on her leadership could ultimately lead to Brexit being stopped.

The Prime Minister also moved to face down the so-called “Gang of Five” of Eurosceptic Cabinet ministers who want her to renegotiate her Brexit deal as she suggested the terms of the UK’s divorce from Brussels could not be changed.

Mrs May’s comments came as pressure continued to increase on her position as speculation mounted that a no-confidence vote could be triggered within days.

Sir Graham Brady, the chairman of the 1922 Committee of backbench Tories, must receive letters from 15 per cent of the party’s MPs, with the threshold currently set at 48, for a vote to be called.

The number of Tory MPs to have publicly declared sending a letter is now nearing 30 with more believed to have sent letters privately.

Sir Graham, however, said it was "very likely" Mrs May would win a no-confidence vote if one was triggered.

Speaking to the BBC, he said: "It would be a simple majority, it would be very likely that the Prime Minister would win such a vote and if she did then there would be a 12-month period where this could not happen again, which would be a huge relief for me because people would have to stop asking me questions about numbers of letters for at least 12 months."

Mrs May said on Sunday that she was in regular contact with Sir Graham but insisted she did not believe the 48 letter threshold had yet been breached.

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She warned her MPs that a no-confidence vote and a potential change of leadership could disrupt or even halt the UK’s withdrawal from the EU.

She told Sky News: "What it will do is bring in a degree of uncertainty. That is uncertainty for people and their jobs.

"What it will do is mean that it is a risk that we delay the negotiations and that is a risk that Brexit gets delayed or frustrated."

She said replacing her as Conservative leader would not change the fundamentals of the Brexit equation.

"It is not going to make the (Brexit) negotiations any easier and it won't change the parliamentary arithmetic,” she said.

Five Cabinet ministers want the Prime Minister to renegotiate her deal to ensure the UK can unilaterally withdraw from the Irish backstop proposal so that the nation is not tied to the EU’s customs union indefinitely.

During her Sky News appearance, Theresa May warned MPs that a potential change of leadership could disrupt or even halt the UK’s withdrawal from the EU credit: Sky News

Mrs May moved to face down Michael Gove, Penny Mordaunt, Andrea Leadsom, Liam Fox and Chris Grayling as she suggested the divorce deal could not be changed.

She said: “There is indeed more negotiation taking place and nothing is agreed until everything is agreed.”

But she added: “We won’t agree the leaving part… until we have got what we want in the future relationship because these two go together.

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“The focus this week will be on the future relationship and when we were in the House of Commons a number of members of Parliament were saying ‘we want some more detail on that future relationship’.

“That’s what we are working on this week.”

Mrs May also revealed that she would be travelling back to Brussels this week to talk to figures including Jean-Claude Juncker, the president of the European Commission.

She said: "I will be going back to Brussels. The negotiating teams are working as we speak and obviously which day I go back to Brussels... will partly be about how those negotiations go.

"I will be going back to Brussels, I will be in touch with other leaders as well, because the summit next week - and it is next week - this special European Council, will be among the European leaders."

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It came as Jeremy Corbyn, the Labour leader, said he did not know how he would vote in a second referendum on the UK's membership of the EU.

Mr Corbyn said he believed another referendum was "an option for the future" and "not an option for today".

05:00PM DUP says withdrawal agreement is 'dangerous'

DUP says withdrawal agreement is 'dangerous'

Democratic Unionist MP Nigel Dodds said his party's opposition to Theresa May's withdrawal treaty has been vindicated.

Labour leader Jeremy Corbyn has claimed his party could get a better deal, while Scottish First Minister Nicola Sturgeon confirmed her MPs would vote against the deal when it goes before Parliament.

There are doubts whether Mrs May's accord will attract enough votes to be passed by the House of Commons.

On Saturday, Sinn Fein President Mary-Lou McDonald ruled out the possibility of her party's seven MPs making the historic move of taking their seats at Westminster to back the deal.

Mr Dodds said the "damning criticism spelt out how dangerous this withdrawal agreement is".

"These are exactly the reasons why Northern Ireland unionism stands united in opposition to this draft Withdrawal Agreement," he said.

"This deal would place a trade border in the Irish Sea, subject us to EU rules without any power to influence or change them and binds us to the EU with no unilateral ability to leave. Indeed, Northern Ireland is part of the EU customs union not the UK's.

"Even Jeremy Corbyn gets it, although nationalists and republicans here are desperate for him to stop saying it."

Mr Dodds added: "I understand why some people fear a 'no deal' scenario. But the choice is between this very bad deal and the right deal.

"With MPs on all sides of the House pointing to the dangers for the Union of the Withdrawal Agreement, it is clear that it is time to work for a better deal which does not undermine the integrity of the United Kingdom."

12:44PM Sir Graham Brady says he is not telling how many letters he has received

Sir Graham Brady says he is not telling how many letters he has received

Sir Graham told the BBC that not even his wife knows how many letters he has received from other Conservative MPs.

"Victoria does not know, nor do the two vice chairman of the 1922 Committee or the other officers."

The senior backbencher also revealed he was not totally happy with Mrs May's withdrawal agreement.

Asked about the deal's lack of a unilateral exit route from the backstop, Sir Graham said: "I'm not happy about it.

"We've got the draft withdrawal agreement, there might be some tweaks to that and I hope there will be."

Graham Brady credit: PA

12:31PM SNP will vote against PM's withdrawal plan, Sturgeon says

SNP will vote against PM's withdrawal plan, Sturgeon says

Nicola Sturgeon has said SNP MPs will vote against the Prime Minister's EU withdrawal plan, and she hopes to sit down this week with Labour and others to formulate an alternative.

Scotland's First Minister told the BBC's Andrew Marr Show the draft agreement lacked clarity on the UK's future relationship with the EU, and the Commons was going to be asked to endorse a "blindfold Brexit".

Outlining what she said were potential alternatives, Ms Sturgeon said: "If the House of Commons says we want to go down the road of single market and customs union membership, we want more time to take this back to the people of the UK in another vote, we need an extension of Article 50 - if there is a clear change of direction - then I believe the EU 27 would be prepared to look at that.

Nicola Sturgeon credit: PA

"But that means those who don't want this deal coming together.

"Those who don't think the Prime Minister's deal is the right way to go have now a responsibility to come together and coalesce around an alternative.

"I will seek to have discussions this week with other parties to get us into that position."

12:26PM Sir Graham Brady says May would likely win no-confidence vote

Sir Graham Brady says May would likely win no-confidence vote

Sir Graham Brady said it was "very likely" Mrs May would win a no-confidence vote if one was triggered.

Speaking on the North West edition of the BBC's Sunday Politics programme, he said: "It would be a simple majority, it would be very likely that the Prime Minister would win such a vote and if she did then there would be a 12-month period where this could not happen again, which would be a huge relief for me because people would have to stop asking me questions about numbers of letters for at least 12 months."

He said both he and the Prime Minister could technically put in letters calling for a confidence vote but that he would be "very surprised" to receive a letter from himself.

11:18AM Dominic Raab: Key points

Dominic Raab: Key points

The former Brexit secretary who quit the Government last week over Theresa May's Brexit deal was on the BBC's Andrew Marr Show this morning.

He said the Brexit deal achieved was "fatally flawed" but could be remedied by just "two or three points" being changed.

He said that the customs backstop plan meant that the UK would remain tied to the EU with no say and no way of independently freeing itself.

Mr Raab said: "The argument is made 'let's get this over the line and play for the second half, the future relationship negotiations'.

"But... it would tilt the advantage in favour of the EU and prejudice, frankly taint, the second phase of negotiation.

"So I think it is a fatal flaw and the shame of it is I have supported this PM all the way through her premiership - I still do now.

Dominic Raab, the former Brexit secretary credit: i-Images

"We were close to a deal and actually if these two or three points were changed I still think a deal could be done but it is very late in the day now and we need to change course."

Mr Raab later accused the EU of "blackmail" and said the Government's political will was lacking in negotiations.

He said: "I do think we are being bullied, I do think we are being subjected to what is pretty close to blackmail frankly.

"I do think there is a point at which, we probably should have done it before, were we just say 'I'm sorry this is the United Kingdom of Great Britain and Northern Ireland, we cannot accept those dictated terms'."

Asked if he believed the deal was worth the £39 billion "divorce bill", Mr Raab gave a simple "no".

The former Brexit secretary also said that he still supported the Prime Minister and would not support a leadership challenge against her.

He said: "I will support this Prime Minister and I want her to get this right."

11:13AM Theresa May: Key points

Theresa May: Key points

The Prime Minister also gave an interview to Sky News this morning.

On whether she had considered quitting, she said: "No I haven't.

"Of course it has been a tough week, actually these negotiations have been tough right from the start, but they were always going to get even more difficult right toward the end when we are coming to that conclusion."

She revealed she is going back to Brussels this week to meet with Jean-Claude Juncker, the European Commission president.

She warned party rivals thinking of replacing her as Conservative leader: "It is not going to make the (Brexit) negotiations any easier and it won't change the parliamentary arithmetic."

Theresa May, the Prime Minister credit: Henry Nicholls/Reuters

Mrs May later revealed that she had spoken to Sir Graham Brady, who chairs the powerful backbench 1922 Committee, and as far as she was aware the required number of Tory MPs' letters to trigger a no-confidence vote in her had not been reached.

She said: "I spoke to Sir Graham Brady at the end of last week, I have regular conversations with Sir Graham Brady.

"Graham Brady will make it known if 48 letters are reached, Graham Brady will make it known."

Asked if the 48 letter threshold had been reached she added: "As far as I know, no, the answer to your question is no."

Regarding a change of leadership, Mrs May added: "What it will do is bring in a degree of uncertainty.

"That is uncertainty for people and their jobs.

"What it will do is mean that it is a risk that we delay the negotiations and that is a risk that Brexit gets delayed or frustrated."

11:10AM Jeremy Corbyn: Key points

Jeremy Corbyn: Key points

The Labour leader was on Sky News this morning.

He said he does not know how he would vote in a second referendum on the UK's membership of the EU.

The Labour leader also revealed that he believed another referendum was "an option for the future" and "not an option for today".

Mr Corbyn also told how his party "couldn't stop" Brexit because of parliamentary arithmetic.

Mr Corbyn also savaged Theresa May's Brexit deal, describing it as a "one-way agreement" in which the EU "calls all the shots".

He said: "We'll vote against this deal because it doesn't meet our tests. We don't believe it serves the interest of this country, therefore the Government have to go back to the EU and renegotiate rapidly.

Jeremy Corbyn credit: Leon Neal/Getty Images Europe

"There's 500 pages in this document much of which is quite vague, where's the guarantee on environmental protections, where's the guarantee on consumer protections, where's the guarantee on workers' rights?"

Asked if he could stop Brexit, the Labour leader said: "We couldn't stop it because we don't have the votes in Parliament to do so."

He added: "There was a referendum in 2016, a majority voted to leave the EU, there are many reasons why people voted. I don't think you call a referendum and then say you don't like the result and go away from it, you've got to understand why people voted and negotiate the best deal you can."

Asked if he would support Remain in a second referendum, he said: "I don't know how I am going to vote, what the options would be at that time."