THE threat to the Union from a no-deal Brexit appeared uppermost in Theresa May’s mind when she addressed colleagues at a crisis Cabinet this morning.

Downing St was particularly reticent about what went on during the emergency get-together or indeed what the Prime Minister’s next move would be as she prepares to address the Commons this afternoon with a statement following last week’s European Council.

But Mrs May opened the discussion with her senior colleagues by making clear a no-deal Brexit was no longer a viable option as Westminster would not allow it.

David Mundell has in recent times been clear that the biggest threat to the Union is a no-deal.

Indeed, the Scottish Secretary is particularly mindful about the issue of his resigning over Brexit because he knows what added impact it would have on the constitutional question in Scotland; that is, Nicola Sturgeon and the SNP would have a field day if Mr Mundell ever left the Government; from his perspective, it would simply boost the independence cause.

The First Minister has repeatedly said Brexit has boosted the independence cause. She is still waiting to see how the withdrawal process plays out before announcing her own "next steps" on Scotland's future.

During Cabinet, sources indicated that Mrs May seemed to be moving more firmly towards ruling out a no-deal outcome, which seemed not to go down too well with the likes of the Leavers such as Andrea Leadsom and Chris Grayling and others who were Remainers but are now thought to be in the Leave camp like Jeremy Hunt, Sajid Javid and Liz Truss.

This was “the first time she has said it so definitively,” said one minister, noting: “It is the issue of the Union[that] seems to be what has really convinced her.”

Minutes after Cabinet, the PM was on the phone to Arlene Foster, leader of the Democratic Unionist Party, whose beef over the backstop has meant the Government’s deal has been in stasis. It was suggested nothing has changed, which is likely to mean Mrs May will not bring forward a third meaningful vote or MV3 on her deal tomorrow or Wednesday. No 10 refused to be drawn on the issue.

The condition the EU laid down to grant an extension to May 22 was that MPs would have to back her deal; if they did not it would only be to April 12.

Tonight, MPs are expected to vote on an amendment put forward by the Conservatives’ Sir Oliver Letwin and Labour’s Hilary Benn, which would, if successfully passed, mean there would be so-called indicative votes on a range of options on Wednesday.

The Government is particularly fearful that this could lead to a constitutional upheaval. Sir Oliver made clear that Wednesday would just be the beginning of the process; that there could be more votes to whittle things down to just one option. Then MPs could vote to “mandate” the Government to go back to Brussels to negotiate on its terms.

The PM’s spokesman noted: “She has said that tying the Government’s hands in this way by seeking to commandeer the Order Paper would have far-reaching implications for the way that the UK is governed and the balance of powers and responsibilities in our democratic institutions.”

Ministers feel such a move is fraught with danger as the Government would have no control and would constantly have to report back to MPs to get their approval or indeed instruction on how things would proceed.

Kit Malthouse, the Housing Minister, who has put forward a managed no-deal proposal with support from both wings of the Tory Party, said: “I hope members across the House realise that it has significantly detrimental constitutional implications and will vote it down so that we can continue with an orderly, iterative process of reaching consensus across the house rather than a kind of X Factor.”

After the weekend’s talk of a coup, Mrs May’s spokesman said no minister raised the issue of her departure. He stressed: "The sense I took from the PM and the Cabinet this morning was of a determination to do whatever it takes to get a deal, so the UK can leave the EU as soon as possible. There is a real sense amongst the Prime Minister and the Cabinet of just wanting to get on with this and deliver for the British people."

However, one source suggested the question of the PM's political future was "the elephant in the room" while another said Cabinet “felt a bit like a farewell speech”.

Tory backbencher Nigel Evans, a joint executive secretary of the influential Conservative 1922 Committee, said Mrs May should set out her plans to quit to get her Brexit deal through.

"Clearly a number of people do not want the Prime Minister anywhere near the next phase of negotiations, which is the future trading relationship between ourselves and the EU," he told BBC Radio 4’s Today programme.

He explained there should be an "orderly" process to replace the Prime Minister, with a full leadership contest rather than an interim successor.

Katie Perrior, Mrs May's former Downing Street director of communications, also argued it was time for the PM to announce her departure date to get her Brexit deal through.

Writing in The Times, she said: "Maybe it's time to stop finding scapegoats and admit that Theresa May and her lack of leadership has made a bad situation worse.

"With great sadness, it's time for her to swap her departure date in return for the deal. It's the least she can do."

Former minister Greg Hands added: “If the PM leaving gets the Withdrawal Agreement across the line, then she ought to put the national interest first and go.”

However, given the turmoil gripping the Tory Party at present it is not certain even the offer of a resignation date would convince some of Mrs May’s colleagues to back her deal.

In a separate development, Mrs May met Jeremy Corbyn to talk Brexit and had a "frank and comprehensive exchange of views," a Labour spokesman said.

The meeting was also attended by Stephen Barclay, the Brexit Secretary, and Julian Smith, the Chief Whip, together with their opposite numbers Sir Keir Starmer and Nick Brown.

"Jeremy Corbyn and Theresa May met for over an hour in Parliament and had a frank and comprehensive exchange of views,” said the Labour spokesman.

"Jeremy Corbyn made clear there was no basis for bringing back the meaningful vote on Theresa May's deal for a third time. The Labour leader did not accept the Prime Minister's suggestion that the Withdrawal Agreement could be separated from the Political Declaration."