- Theresa May is on course for a humiliating Commons defeat over her Brexit deal
- Remainer rebels plotting to strip government of control over Commons business
- No10 fears the move could mean it is impossible for the government to carry on
- Speaker John Bercow said to be ready to help the Remainer plot against the PM
- Mrs May warned failing to deliver on 2016 referendum would be a 'catastrophe'
- Jeremy Corbyn hinted he will force no-confidence vote this week if deal fails
Theresa May is facing an all-out bid by Remainer rebels to stop Brexit going ahead by tearing up the Commons rulebook.
The 'coup' could see the government stripped of control over business in Parliament - paralysing the PM and potentially allowing MPs to prevent the UK crashing out without a deal.
The move - which No10 believes is being orchestrated by former ministers Oliver Letwin and Dominic Grieve - could happen within hours of Mrs May's Brexit plan being heavily defeated on Tuesday, as seems inevitable.
The manoeuvring was only uncovered by Chief Whip Julian Smith when he overheard conspirators in the MPs' cloakroom.
Ministers have been warned success for the plotters could make it impossible for the government to cling on.
There are claims Speaker John Bercow is ready to help the backbench uprising, after he secretly met Mr Grieve last week.
The high-stakes battle emerged as Mrs May launched another desperate effort to salvage the package she has thrashed out with Brussels.
Mrs May said failing to deliver on the verdict of the referendum would be 'unforgivable' and a 'catastrophe' for democracy.
At the start of an historic week in Parliament that could make or break Brexit:
- Former PM Sir John Major has joined calls for Article 50 to be revoked to give the UK more time, reiterating his support for a second referendum.
- Mrs May is still thought to be on track for a huge defeat on her Brexit deal, with speculation it could be the biggest ever suffered by a government.
- Cabinet ministers have warned of a 'Brexit bunfight' between supporters of alternative policies if Mrs May's package is killed off.
- Hopes are fading of significant concessions from the EU before the crunch Parliamentary clash.
- Jeremy Corbyn hinted Labour is preparing to force a no-confidence vote this week if the premier loses the Commons showdown.
- Fourteen military planners are said to have have been deployed to Whitehall departments to help with preparations for border chaos if the UK crashes out.
Hardline Remainers and Brexiteers have been mobilising in a bid to thwart her plans.
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, warning it was a 'real threat' to its ability to function.
The government currently has power to control business in the chamber - which is especially crucial when there is no overall majority.
The executive proposes legislation and motions, which are then scrutinised by MPs.
But ripping up the system to give backbenchers priority over Parliamentary time could fundamentally change the balance.
MPs would be able to prevent ministers bringing forward legislation, and stage votes on what should happen next - potentially even binding ones.
The tactic apparently emerged when one of the conspirators was overheard in the MPs' cloakroom by Mr Smith.
He reportedly sought advice from legal experts, who said: 'Such an attempt represents a clear and present danger to all government business.
'Without control of the order paper, the government has no control over the House of Commons and the parliamentary business and legislation necessary to progress government policies. The government would lose its ability to govern.'
The ex-head of legislation at No10, Nikki da Costa, said she had 'never seen something so designed to undermine government stability'.
She said the amendments required to make the overhaul happen would 'normally not be in scope' and 'shouldn't be possible'.
'But with this Speaker... if passed it would be catastrophic,' she added.
'I don't say that lightly. I've never seen something so designed to undermine government stability.'
Asked about the claims, Brexit Secretary Stephen Barclay said: 'What recent events have shown, with events over the last week with what happened on the legal advice where the Government was forced to act in a way it didn't want to, is the uncertainty in terms of what will happen in the House has increased.
'So those on the Brexiteer side seeking ideological purity with a deal are risking Brexit, because there is a growing risk that events could unfold in ways that (mean) they are leaving the door ajar to ways that increase the risk to Brexit.'
Mr Grieve is said to have refused to deny he is involved in the scheme. The PM's allies have also pointed the finger at ex-minister Sir Oliver Letwin, while other Tory MPs including Nick Boles, Anna Soubry and Sarah Wollaston have pledged to support any measures necessary to avoid a no-deal Brexit.
Ms Soubry today tweeted accusing Downing Street of 'nasty smear tactics' against Mr Grieve and other Remainers, designed to 'scare' politicians into backing the PM's agreement.
Labour's Chris Leslie, another of those coordinating efforts to avoid no-deal Brexit, said: 'MPs saying ‘no’ to Executive isn’t a ‘coup’. It’s parliamentary democracy in action.
'It’s Ministers who consistently try to overrule Parliament: stacking committees; forcing through Henry VIII powers; withholding papers; breaking pairing; trying to trigger Brexit with no vote.'
The Mail on Sunday has revealed that Mr Grieve secretly met Mr Bercow last week just hours before the Speaker threw out centuries of tradition to scupper Mrs May's Brexit plans.
The pair spoke in Mr Bercow's grace-and-favour Commons apartment the day before the Speaker tore up the rule book to allow the former Attorney General to table an amendment forcing the PM to table a 'Plan B' within three days of her expected defeat.
Ministers believe the Speaker will do 'almost anything' to block the government, with senior sources telling MailOnline it is 'terrifying' that Mr Bercow holds the key to their fate.
Conservative Party chairman Brandon Lewis said Britain was facing 'Brexit paralysis' if her plan was rejected by MPs.
Tory ex-PM Sir John Major today called for Article 50 to be revoked to give the UK more time, saying it was the 'only sensible course'.
Jeremy Corbyn has so far resisted pressure to force a vote, with allies insisting there is no point as the government would win.
But there are mounting signs that he is ready to take advantage of Mrs May's moment of maximum weakness.
Mr Corbyn made clear the party is on high alert to try to force the PM out and a general election.
He suggested the Brexit date will have to be delayed if he succeeds, but repeatedly refused to be drawn on whether Labour would campaign on a manifesto to take the UK out of the EU.
He also declined to say if he would back a second referendum, as is being demanded by dozens of his own MPs.
In the interview today, Mr Corbyn said: 'The crucial thing is Tuesday. And then, if this Government can't control Parliament, it's time to have a general election.'
Ducking and diving as he was pressed on whether Labour would campaign on a manifesto to deliver Brexit, Mr Corbyn said 'we're campaigning for a country that is brought together by investment'.
He added later: 'We're campaigning for a customs union.'
The Labour leader said his party will 'decide our manifesto content as soon as we know there's an election coming'.
Pressed about the option of a second referendum, Mr Corbyn stressed his preference for a general election.
He added: '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.'
Writing in the Sunday Express, Mrs May pleaded with parliamentarians to 'do what is right for our country' and back her controversial exit plan.
In what she described as the 'biggest and most important decision that any MP of our generation will be asked to make', the Prime Minister said it was time for politicians to 'deliver' for the people.
'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,' she wrote.
'You have delivered your instructions. Now it is our turn to deliver for you.'
Rebel Tories have been warned that forcing a defeat could lead to one of two 'nightmare scenarios'.
Pro-Remain Tory MPs join forces with Labour to compel the UK to stay in a customs union with the EU; or Mr Corbyn moves to bring down Mrs May with an immediate vote of no confidence.
Either way, it could lead to a crushing General Election defeat within weeks unless they fall into line, whips say.
Tory chairman Brandon Lewis told The Mail on Sunday that a 'Brexit bunfight' would 'open up between those who want a second referendum, an extension of Article 50 or a Norway-plus deal'.
Transport Secretary Chris Grayling, pushed about the Government's Brexit Plan B, told Sky News' Ridge on Sunday: 'I'm not going to get into 'will we do this, will we do that, will we do the other?'.
'The important thing is to say to fellow MPs those concerns are out there and the big concerns are: Are we going to leave? Are we going to deliver Brexit? Are we going to somehow try and reverse Brexit? Is Parliament going to force us to reverse Brexit?
'What we have is a sensible compromise deal. It's not giving everybody everything what they want, but it was never going to - this was a 52-48 result.'
Labour added to the pressure last night by announcing that Mr Corbyn would unveil a new party political broadcast on Wednesday in which he would 'spell out how Labour plans to unite and rebuild the country' and 'campaign on a growing view that austerity and inequality has created a country of haves and have-nots'.
The party also announced that it was hiring pollsters for the next Election 'to test policies and the impact of campaigning in key marginals' and had selected 100 candidates for the closest-fought seats.
Labour sources claimed that the most recent polling showed that the country has 'moved economically to the Left'.
One said: 'While the Government has been locked in bitter infighting and chaos over their botched Brexit negotiations, the needs of the country have been neglected. Tory austerity has left the majority of people worse off, creating a cost of living crisis and levels of poverty not seen since the 1930s.
'Our Election campaign strategy will set out a positive vision of how we will make the country better, one of fairness and good public services, where we support each other.'