THERESA May is to rule out a no-deal Brexit outcome ahead of the “moment of truth” Commons vote on February 27, a Cabinet source has told The Herald.

As MPs prepare for this evening’s series of votes with Tory Brexiteers seemingly pulling back from a move to defeat the Government, the senior minister made clear Mrs May would come up with “a form of words” that would satisfy Parliament and her own Cabinet colleagues that she would not allow the UK to leave the EU without an agreement on March 29.

Another Whitehall source predicted that the reassurance would come in the Government motion, which will be tabled in the hours before the February 27 debate and vote.

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He suggested, if the PM’s reassurance were as firm as colleagues hoped, then it would negate the need for people to vote for the Government’s main threat: the amendment set down by Labour’s Yvette Cooper, which says that if the PM has not got a deal through Parliament by March 13, then MPs would either have to vote to agree a no-deal Brexit or force the PM to seek an extension to the Article 50 process.

“February 27 will be the moment of truth,” declared the senior Government source. “It’s when people will have to make a decision.”

This was an indirect reference to Cabinet colleagues like Amber Rudd, David Gauke and Greg Clark, who have dropped heavy hints that they could not be part of a government that allowed Britain to fall off a Brexit cliff-edge without a deal and would resign.

The revelation by the senior minister that Mrs May will, by February 27, effectively reject the possibility of a no-deal outcome will be meant to avert such a Cabinet rebellion.

However, it is in direct conflict with the PM’s current position, which is, that the only way a no-deal Brexit can be ruled out is either by agreeing a deal or revoking Article 50.

On Wednesday, her spokesman made clear: “If you’re asking me a question of does no-deal remain on the table, the answer is yes.”

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But a rejection of this position would also spark a major backlash from Tory Brexiteers, who believe keeping the option of a no-deal outcome on the table adds to Britain’s negotiating strength with Brussels.

Of course, Mrs May is seeking to strike a new deal with Brussels “as soon as possible” and, theoretically, could secure an agreement with the EU by February 27. But most observers believe this to be highly unlikely and that the process will move towards the key vote at the end of the month.

While like tonight’s vote, the one on February 27 will be a next-steps decision, which will not be legally binding, the Whitehall sources made clear, politically, it will be enormously important.

One referred to it as a “semi-meaningful vote”. The meaningful vote on the PM’s fully-formed Plan B is not expected until March.

As MPs began their latest debate on Brexit the prospect of defeat for Mrs May appeared to be receding after leading Brexiteer Jacob Rees-Mogg suggested it was "highly unlikely" that Eurosceptic Tories would rebel after all.

Members of the backbench Conservative European Research Group had threatened to vote down a Government motion, which they said effectively endorsed efforts to block a no-deal Brexit.

But ministers warned that defeat for the PM would send the "wrong signal" to Brussels about the possibility of Parliament uniting behind the revised Withdrawal Agreement which Mrs May is seeking.

Liam Fox, the International Trade Secretary, told potential rebels that Parliament was not an "internal debating society" and European negotiators would be watching to see if MPs were showing "consistency".

"What we say is looked at and listened to by those that we are negotiating with," the Scot told BBC Radio 4's Today programme.

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"They will be looking to see whether Parliament is showing consistency because in the debates and the votes we had recently there were two things: one was that Parliament said we don't want there to be no-deal and that we will sign up to the Prime Minister's deal if we are able to get changes to the Irish backstop.

"Our European partners will be watching our debate and listening today to see if they get the impression that if they were to make those concessions, Parliament would definitely deliver on that."

However, Steve Baker, the former Brexit minister, argued Conservatives should not be "associated with anything" that "seems to take no-deal off the table".

Members of the ERG have been lobbying Downing Street for two days to amend the wording of Mrs May's motion for the Valentine's Day vote, which asks the Commons to "reiterate" its support for the approach approved in an earlier set of votes on January 29.

MPs voted on that date to send Mrs May back to Brussels to seek an alternative to the "backstop" provisions in her EU Withdrawal Agreement which are intended to ensure the Irish border stays open after Brexit.

But they also gave a majority the same day to a non-binding amendment calling on the Government to rule out a no-deal outcome.

Some Eurosceptics would welcome no-deal, while others believe it must be kept as a weapon in the Government's armoury to ensure maximum leverage in extracting concessions from the EU.

Speaking as Downing Street confirmed it would not amend the wording of the motion, backbencher Lee Rowley said: "The Government is essentially asking me to vote for something tonight - taking no- deal off the table - which isn't Government policy.

"We are all genuinely scratching our heads this morning asking what on earth they are doing. Instead of putting forward badly worded motions, the Government should be properly focusing on the Malthouse compromise - the one and only option which brings together Leavers and Remainers and, vitally, will command a majority in Parliament."

ERG members declined to confirm whether there would be a rebellion or speculate on possible numbers involved.

But Mr Rees-Mogg, the group's chairman, signalled three hours before voting was due to take place that the potential revolt was off.

He told ITV News: "This is a secondary issue, rather than a primary one, and that is why it is highly unlikely people will be voting against this motion."

Mrs May's spokesman told reporters: "It is important that MPs support the Prime Minister today in order to send another clear message to Brussels on the need to address Parliament's concerns about the backstop, so we can leave on time with a deal on March 29."

John Bercow, the Commons Speaker, selected only three of the 10 amendments tabled for debate on the floor of the Commons.

MPs are set to vote on a Labour amendment demanding that Mrs May hold a meaningful vote on her plan by February 27 or hand power to Parliament to decide the next steps.

Also selected were an SNP amendment calling for a three-month extension to Brexit negotiations and a demand from pro-EU backbenchers led by Tory Anna Soubry for the publication of the latest official assessments of the likely economic impact of no deal.

The latest showdown comes as Dutch PM Mark Rutte told the Financial Times the Netherlands was already benefiting from businesses relocating from a "diminished" Britain.

But Mrs May's spokesman insisted Number 10 "disagrees entirely" with Mr Rutte's stance, adding: "Employment is at a record high, exports are at a record high, companies are continuing to invest in the UK.

"Deloitte named the UK as Europe's leading destination for foreign direct investment and London as the world's top city for investment just last month."

In a bid to keep lines open with EU leaders, Mrs May spoke to French President Emmanuel Macron and Romanian President Klaus Iohannis on Wednesday evening and is expected to make further phone calls over the course of Thursday.

People's Vote protesters seeking a second EU referendum gathered outside Parliament to demonstrate against what they termed a "blindfold Brexit".

And pro-Brexit campaigners from the Leave Means Leave movement delivered a Valentine's Day card for the PM to Downing Street.