JEREMY Corbyn says he will table a no-confidence vote in Theresa May’s Government “soon” if, as expected, her Brexit Plan is voted down on Tuesday.

As Westminster faces its most momentous week for generations, the Labour leader also made clear he believes Labour should campaign for a soft Brexit in any snap general election on the back of the Prime Minister losing that confidence vote but acknowledges it will be the party that will decide on what will be in Labour’s election manifesto.

His comments came after Mrs May warned of a "catastrophic and unforgivable breach of trust" in democracy if MPs did reject her Brexit deal this week and the UK remained in the European Union.

Appearing on the BBC’s Andrew Marr Show, Mr Corbyn said the PM was in “desperate stakes” said that the UK-EU Withdrawal Agreement would be "very damaging in the long run" to rights, trade arrangements and to the Northern Ireland situation.

He said: "We will table a motion of no-confidence in the Government at a time of our choosing but it's going to be soon, don't worry about it."

Repeatedly asked whether or not Labour would campaign to Leave the EU if there were a general election, the party leader sidestepped the question but declared: "We're campaigning for a country that is brought together by investment…We're campaigning for a customs union."

He later explained the party would "decide our manifesto content as soon as we know there's an election coming".

Asked if Article 50 should be extended, Mr Corbyn suggested it should, saying: "Clearly, if Theresa May's deal is voted down, clearly, if a general election takes place and a Labour government comes in - an election would take place February, March time – clearly, there's only a few weeks between that and the leave date, there would have to be time for those negotiations."

Pressed about a second referendum, the Labour leader outlined his party’s hopes for a general election first, before saying: "My own view is that I'd rather get a negotiated deal now, if we can, to stop the danger of a no-deal exit from the EU on March 29, which would be catastrophic for industry, catastrophic for trade and the long-term effects of that would be huge."

In response, Brandon Lewis, the Conservative Chairman, said: “Jeremy Corbyn wants a general election on Brexit but this morning failed five times to say what he would actually do on Brexit.

“He also confirmed Labour would delay Brexit by extending Article 50; perhaps because he needs time to make up his mind.

“On top of that, he made clear he has absolutely no interest in getting control of our borders after we leave the EU.”

Mr Lewis added: “One thing is clear: instead of acting in the national interest, Jeremy Corbyn is playing politics and would take the county back to square one.”

Earlier on the Marr programme, Stephen Barclay, the Brexit Secretary, repeatedly challenged on what would happen if Mrs May’s Plan were rejected on Tuesday, failed to say what Plan B was or, indeed, if there was a Plan B, saying only that he suspected the Commons would support something "along the lines of this deal".

With just two days to go before the Commons votes on her withdrawal agreement, the PM pleaded with parliamentarians to "do what is right for our country" and back her controversial exit plan.

She claimed the UK risked crashing out of the EU without a deal or if MPs were "unwilling" to face the uncertainty of a no-deal, then the UK might not leave at all.

In what she described as the "biggest and most important decision that any MP of our generation will be asked to make", Mrs May said it was time for politicians to "deliver" for the people.

Writing in the Sunday Express, she said: "You, the British people, voted to leave. And then, in the 2017 General Election, 80 per cent of you voted for MPs who stood on manifestos to respect that referendum result. You have delivered your instructions. Now it is our turn to deliver for you.

"When you turned out to vote in the referendum, you did so because you wanted your voice to be heard. Some of you put your trust in the political process for the first time in decades. We cannot - and must not - let you down.

"Doing so would be a catastrophic and unforgivable breach of trust in our democracy. So my message to Parliament this weekend is simple: it is time to forget the games and do what is right for our country."

Her stark warning came as Downing Street said it was "extremely concerned" about a backbench plot to change Commons rules to enable backbench motions to take precedence over Government business if Mrs May's deal fell.

Under the rebels' plan, the Government would lose control of parliamentary business which would threaten Brexit legislation and the Government's own ability to govern.

It emerged John Bercow, the Commons Speaker, met Tory remain rebel Dominic Grieve on Tuesday, the day before his controversial decision to allow MPs a vote on the former Attorney General's amendment to the timetable of the Brexit deal.

A source close to Mr Bercow was quoted as saying: “Tearing up the standing orders is what I would expect to happen. He is setting out to stop Brexit. He’s part of the rebel team.”

A senior government source told The Sunday Times that Mrs May and her aides were “shellshocked” and declared: “This could be game over for Brexit.” Another added: “This sounds very like a very British coup and one that has profound implications for democracy.”

A spokeswoman for the Speaker said: “We have no knowledge of backbench rule changes. The Speaker did meet Mr Grieve on Tuesday. He meets members from both sides of the House and all parties.”

It was suggested details of the so-called plot were now being shared by Tory whips with leading Brexiteers to try to persuade them to support the PM’s Plan and to save Brexit.

Chris Grayling, the Transport Secretary, warned rebels about the potential future consequences of what they might be planning.

“It would be a huge mistake for anyone in Parliament to think that changing the rules in this particular way over Brexit is the right thing to do. It would cause long-term problems for governments of all persuasions to get legislation through. It would change the whole nature of our parliamentary system. It would be a big mistake,” he told Pienaar’s Politics on BBC Radio 5 Live.

Asked if the rebels’ move would simply stop the Government from being able to govern, Mr Grayling replied: “You would not be able to guarantee you could bring forward legislation in the way that Government can do. So, when people say: ‘We need you to do this for us’, Government will no longer be able to guarantee that it can do it.”

As speculation mounted that Mrs May's deal would be defeated:

*the PM faced a call from one of her predecessors, Sir John Major, to revoke Article 50 to halt Brexit as he warned it would be "morally reprehensible" to crash out without a deal;

*it emerged that 14 military planners have been deployed to four key Whitehall departments to assist with no-deal planning;

*more than 100 MEPs from 26 EU member states signed a letter calling on the UK to "reconsider" the Brexit decision, saying the UK's departure would "weaken all of us" and

*Jean-Claude Juncker, the European Commission President, is preparing to reveal tomorrow the “further assurances” Brussels can give on the Irish backstop. However, few at Westminster believe this will be a game-changer and avert Mrs May suffering a heavy Commons defeat on her Plan.