John McDonnell told attendees to his speech at the Edinburgh Festival Fringe that he wants a new law to silence his opponents

John McDonnell says Labour would demand the keys to No10 from Boris Johnson if he loses a confidence vote but refuses to quit.

The Shadow Chancellor said he would be 'sending Jeremy Corbyn in a cab to Buckingham Palace', at an Edinburgh Festival Fringe event.

It comes after allies of the PM have made clear he will simply refuse to resign if rebel Tories join forces with Labour, the SNP, the Lib Dems and independents to pass a no confidence motion.

Mr McDonnell said: 'I don't want to drag the Queen into this but I would be sending Jeremy Corbyn in a cab to Buckingham Palace to say, 'we're taking over'.'

Labour has refused to back a plan from anti-No Deal Tory rebels to install a short-term 'government of national unity' led by a Labour backbencher to stop No Deal.

Instead, the party wants Mr Corbyn to be installed as leader of a 'caretaker' government.

McDonnell told listeners that Jeremy Corbyn (left) might have to appeal to the Queen if Boris Johnson lost a confidence vote but refused to quit as Prime Minister

Mr McDonnell came under fire for other comments at a different event at the popular Scottish festival, where he said he 'might want to invent' a law to lock up Conservative MPs he has branded 'social criminals' for cutting benefits.

Tory MPs seized on the remarks, saying they showed Mr McDonnell was unfit for high office.

Call for law change to avoid food shortages The British food industry has demanded ministers waive aspects of competition law to enable them to cope with the risk of a No Deal Brexit. The Food and Drink Federation wants to allow firms to co-ordinate and direct supplies with each other. Doing so is illegal as the law stands. Firms say, due to stockpiling for Christmas, leaving the EU in the autumn could mean there will be less warehouse space for extra food supplies. The Road Haulage Association is also warning that lorry drivers in Dover face sitting in two-day-long queues without food or toilets if Britain leaves the EU without a deal. Advertisement

A source close to Mr McDonnell said the comments were a 'joke,' pointing out he was speaking 'at Edinburgh festival where no speech should be without a joke'.

But Treasury minister Simon Clarke said: 'These are not the comments of a man fit to be Chancellor – or to hold any office – in a Western democracy. A blatant affront to the rule of law.'

Tory MP Paul Scully added: 'It comes as little surprise McDonnell wants to invent laws to silence opponents.

'This is a man with a sinister history, who has called for a female MP to be lynched, 'direct action' against opposing MPs and praised the bombs and bullets of the IRA.'

Mr McDonnell was criticised in 2014 for repeating comments saying former work and pensions secretary Esther McVey deserved to be 'lynched'.

Ian Austin, an MP who left Labour this year, tweeted: 'Can you imagine any senior Labour figure of the past threatening to lock up Tory MPs for voting for laws they didn't like?

'What would people like McDonnell call Right-wing politicians who send opponents to prison?

No 10 chief's chilling warning to rebels By Claire Ellicot, Political Correspondant Boris Johnson's top adviser yesterday warned MPs trying to prevent a No Deal Brexit: 'You don't get to choose which votes you respect.' Former Vote Leave chief Dominic Cummings said preparations for leaving the EU on October 31 without a withdrawal agreement were going 'great'. He was yesterday asked about comments made by pro-Remain Tory MP and former attorney general Dominic Grieve. Mr Grieve had attacked the No 10 adviser's 'characteristic arrogance and ignorance' for reportedly saying it was now too late for MPs to stop No Deal with fewer than 90 days until the October 31 deadline. Mr Cummings told Sky News: 'I don't think I am arrogant. I don't know very much about very much. Mr Grieve will see what he's right about.' He added: 'The most simple thing is, the Prime Minister believes politicians don't get to choose which votes they respect – that is the critical issue.' Meanwhile, it was claimed last night that Britain could go to the polls the day after a No Deal Brexit. A general election could be called on November 1, The Spectator reported. Last night, a senior Government source said: 'It's speculation. The only date we are thinking of is October 31 – the day we leave the EU.' Advertisement

'These people are extremists and they've poisoned the Labour Party.'

Chancellor Sajid Javid said the comments showed Mr McDonnell was 'not fit to be an MP, let alone Shadow Chancellor'.

Mr McDonnell's remarks were made in an interview conducted by broadcaster Iain Dale on Tuesday afternoon on the Edinburgh Festival Fringe.

Dale quizzed the Shadow Chancellor on comments he made in September 2011 at a 'Unite the Resistance' conference in which he called Tory MPs 'social criminals'.

The then backbench MP said he wanted to be 'in a situation where no Tory MP can show their face in public without being challenged by direct action', adding: 'They are social criminals and I warn you, we will try them.'

Speaking to Dale, he said he was 'angry' at the time because of 'cuts on disability benefits'.

He claimed he had 'never advocated violence, but I have advocated direct action'. Asked whether he could really 'try' politicians in a court of law, Mr McDonnell said: 'I wouldn't mind it actually.'

Shadow Treasury minister Clive Lewis yesterday called for a general strike over climate change – despite Britain having reduced emissions faster than any other G20 country. The proposed date is September 20, weeks after children return to school following the summer holiday.

Boris Johnson would trigger the biggest crisis since Charles I was BEHEADED if he refuses to quit after losing confidence vote, former foreign secretary warns

Boris Johnson will trigger the biggest constitutional crisis since Charles I was beheaded if he refuses to quit after losing a Commons confidence vote, a Tory former foreign secretary warned today.

Sir Malcolm Rifkind delivered the stark message after allies of the PM made clear he will try to cling on if he is defeated on a critical motion by rebel Tories, Labour, the SNP, the Lib Dems and independents.

Instead of resigning, Mr Johnson could wait for an election to be triggered and use his executive powers to set the date of an election for after the Brexit deadline of October 31, so MPs cannot stop the process.

The idea has sparked fury among Remainers, who insist such a tactic would force the Queen to step in and sack the PM.

Sir Malcolm added his voice to the condemnation today, saying Mr Johnson risked causing the worst crisis since the Civil War in the 17th Century.

Boris Johnson (pictured at No10 today) has been warned he will trigger the biggest constitutional crisis since Charles I was beheaded if he refuses to quit after losing a Commons confidence vote

Sir Malcolm said Mr Johnson should 'slap down' his maverick Brexit aide Dominic Cummings (pictured at No10 today) over claims he could defy constitutional norms to cling on

He insisted Mr Johnson should 'slap down' his maverick Brexit aide Dominic Cummings, who apparently 'laughed' during a meeting when it was put to him that the PM would have to quit after a confidence vote.

'If the prime minister refused to respect the normal consequence of losing a confidence vote and if he sought to prevent both parliament and the electorate having a final say on No Deal, he would create the gravest constitutional crisis since the actions of Charles I led to the Civil War,' Sir Malcolm wrote in a letter to The Times.

'I have great confidence that the prime minister will ignore the advice of Dominic Cummings. King Charles lost his head by flouting the constitution. Mr Johnson will wish to keep his, while some around him are, clearly, losing theirs.'

Mr Cummings broke his public silence to hit back at Tory former Cabinet minister Dominic Grieve, who accused him yesterday of 'arrogance'.

Quizzed by Sky News as he left his London home this morning, the former Vote Leave strategist said: 'I don't think I am arrogant, I don't know very much about very much...

Countdown to Brexit Here are some key dates in the countdown to Brexit: September 3: Parliament returns from its summer recess Early September: Labour is expected to trigger a vote of no confidence in Boris Johnson's Government Early/Mid-September: If Boris Johnson loses the confidence vote, Remainers could try to install a cross-party administration to delay Brexit past October 31 Early/Mid September: Alternatively if Mr Johnson loses a general election is triggered if no one can form an administration within 14 days. But there are few rules on when he has to hold it Early/Mid September: Or the Queen could step in and demand Mr Johnson resign, should he try to remain in No 10, sparking a potential constitutional crisis October 31: Brexit day, when the UK is currently due to leave the EU Early November? A possible post-Brexit General Election Advertisement

'Mr Grieve will see what he's right about.'

Mr Cummings also said: 'The PM believes that politicians do not get to choose what votes they respect.'

Mr Grieve, who is leading efforts to prevent No Deal, described the idea of Mr Johnson clinging on as 'breathtaking, stupid and infantile'.

He said it was an 'utter fantasy' that Mr Johnson could prevent a new government being formed – and suggested the Queen would have to intervene to prevent a constitutional crisis.

Under the Fixed-Term Parliaments Act there is a 14-day period after the loss of a confidence vote.

If no one else gains the confidence of the Commons during this time there is a general election.

Mr Grieve is hoping to install a new cross-party PM, possibly Labour veteran Margaret Beckett, before Halloween to prevent the UK crashing out of the EU.

Only a premier can ask for an extension to the Article 50 process, and the legal default is for Brexit to happen by the deadline with or without a deal.

However, some people believe Mr Johnson has no legal obligation to quit as Prime Minister, and could stay to ensure any election was held after Brexit on October 31, preventing attempts to scupper No Deal.

Mr Grieve said: 'A prime minister defeated in a motion of no confidence cannot sit out the 14 days and prevent a new government being formed if it has the support of the Commons.

'If he were to refuse to resign to allow that to happen... the Queen would have to sack him. She is the ultimate guardian of our constitution. That's her job. Unless you want to tear up the constitution we shouldn't go down the route advocated by Boris Johnson.'

Businesswoman and campaigner Gina Miller suggested it would be 'unlawful' if Mr Johnson refused to step down.

She said the Fixed-term Parliaments Act is 'governed by convention', telling BBC Radio 4's Today programme: 'There is a solid convention that a prime minister losing a vote of no confidence must step down.'

Ms Miller previously went to court and won the right for Parliament to give its consent ahead of the Government triggering Article 50 to begin the Brexit process.

Mr Johnson met King Abdullah of Jordan for talks in Downing Street this afternoon

She added: 'While the Fixed-term Parliaments Act does not replace convention, it can be said the frustration of the principle - which is actually what we invoked in my first case and we won - would be in play because Prime Minister Johnson's refusal to go would frustrate the operation and the purpose of the Act, and therefore be unlawful.'

Asked if she could be granted a judicial review in time, Ms Miller replied: 'I have already instructed my legal team to take whatever steps necessary to ensure that a prime minister doesn't attempt to put themselves above the law, and that we would seek some judicial review and clarity.

'That is already in motion and we would be ready.'

However, in a blow to Remainers, Labour's shadow business secretary Rebecca Long-Bailey insisted the party will not support a 'national government of unity' to stop No Deal.

Speaking to Channel 4 News last night, she said: 'We're quite clear that we're happy to collaborate on a cross-party basis, but we wouldn't countenance a national government of unity, as it were, because we think that we need to have a clear majority for a government in Parliament.

'That's why we're calling for a general election and we're fighting for a Labour majority.

'What we don't want is a national unity government that gives Boris some sort of get out of jail free card, so as soon as Brexit's been sorted out, he can sail back in without any problems at all, without a sufficient parliamentary majority.

'That simply wouldn't be right.

'We think that this is a decision that needs to be put back to the people and that's why we want to have a general election.'

Tory former attorney general Dominic Grieve (pictured left in Westminster last month), who is leading efforts to prevent No Deal, described the idea of Mr Johnson clinging on as 'breathtaking, stupid and infantile'. Sir Malcolm (right) said the PM should 'slap down' his adviser Mr Cummings

Under the Fixed-term Parliaments Act, the PM has significant discretion on the election date even if they have failed to secure the confidence of the Commons

How the Queen could be dragged into a constitutional crisis with demands for her to SACK Boris Johnson as MPs and the PM clash over No Deal Brexit

The UK is staring down the barrel of a constitutional crisis as Remainers demand the Queen steps in to stop Boris Johnson forcing through No Deal Brexit.

While the monarch is sovereign, the UK political system relies on her being kept out of politics as much as possible.

In normal times her role is a courtesy one, rubber-stamping Government decisions.

However, pro-EU MPs insist she will have no choice but to sack Mr Johnson if a no-confidence motion is passed in the Commons and he refuses to go voluntarily.

The fuse could be lit on a full-blown constitutional explosion when Parliament returns from its summer recess on September 3.

Here we examine what could happen in the autumn lead-up to Brexit.

Boris Johnson (pictured in Downing Street this week) has solemnly vowed to complete Brexit by October 31 'come what may', but the EU is refusing to give way on his key demand that the hated Irish border be dropped

How has this situation been created?

Mr Johnson is solemnly vowing to complete Brexit by October 31 'come what may', but the EU is flatly refusing to give way on his key demand that the hated Irish border be dropped.

If the stand-off has not been broken by September, Labour is expected to team up with Tory rebels such as former Cabinet minister Dominic Grieve to stage an early confidence vote to stave off the threat of crashing out.

It is a drastic option that would end the careers of any Conservative MPs who join, but only a PM can request an extension to the Article 50 process, and the legal default currently is that the UK leaves at Halloween with or without an agreement.

As the government's working majority is just one and with strong cross-party opposition to No Deal, there is a serious prospect that Mr Johnson will lose.

Labour leader Jeremy Corbyn has said the motion would be tabled at an 'appropriate very early time', suggesting it will be soon after Parliament returns.

What does Downing Street think?

The PM's adviser Dominic Cummings has made clear the prime minister would simply refuse to resign if he lost a confidence vote.

Mr Cummings reportedly 'laughed' at a meeting recently when it was put to him that Mr Johnson would have to quit in those circumstances.

Instead Mr Johnson could try to wait for an election to be triggered and fight it on a 'people vs politicians' ticket, complaining that his opponents are trying to block Brext.

Or as a nuclear option, he could try to fix an election date that was after the Halloween Brexit date - robbing the Commons of its ability to control the process and achieving a No Deal Brexit by default.

Can he do that?

Under the Fixed Term Parliaments Act (FTPA), losing a confidence motion triggers a 14 day countdown to an election being called.

During that period it is possible for a Prime Minister to win a confidence vote and prevent the country going to the polls.

However, the legislation is silent on whether the same premier can return to try again.

Remainers believe if the premier refused to go quietly the Queen would be forced to sack him and a unity Government could be installed, with Margaret Beckett a rumoured interim leader

Remainer MPs insist Mr Johnson would have to quit, suggesting an all-party administration led by a consensus figure - potentially Labour veteran Margaret Beckett - could take over to delay the Brexit process.

They are adamant that if the premier refused to go quietly the Queen would be forced to sack him.

One senior source told MailOnline the monarch would have to intervene before then if Mr Johnson was playing 'childish games' with the constitution.

'We have an unwritten constitution but there are well established conventions,' the MP said. 'Convention number one is that a PM does not or cannot hold office without the consent of the House of Commons.'

How would it work?

If Mr Johnson tried to 'bury himself' in Downing Street and tried to stop a new government taking over, the monarch would step in despite the risks of getting embroiled in politics, the Remainer source said.

'The Queen would write him a letter saying he is dismissed,' they insisted. 'She would have to sack him. Of course she would.'

The plan is for Parliament to indicate its support for a rival PM candidate in a vote, at which point the monarch would invite them to replace Mr Johnson.

However, whether an anti-No Deal alliance could muster the numbers to install a cross-party PM is highly dubious.

It would require Jeremy Corbyn and the Labour frontbench to give up his chance of seizing power.

If the stand-off has not been broken by September, Jeremy Corbyn (pictured at Whaley Bridge this week) is expected to team up with Tory rebels to stage a confidence vote - which Mr Johnson could easily lose

Can it work?

A factor in Mr Johnson's favour is a further loophole in the FTPA, which gives the sitting premier huge discretion on the timing of an election if one is triggered.

The Queen names the date based on recommendation from the PM, but the act does not give any time frame he must work inside.

Pro-EU MPs admit Mr Johnson could legally extend the schedule by at least a month - taking it well beyond the Halloween Brexit deadline.

However, that would set the stage for a massive constitutional showdown, with the civil service under pressure to maintain the 'status quo'.