EIGHT former Cabinet ministers led a devastating revolt against Theresa May to wrestle back control of Brexit.

A total of 26 Tory MPs allied with Labour, the SNP and Lib Dems to force the Government to take orders from the House of Commons if the PM’s deal is voted down in six days time, as ministers expect.

Tabled by former Attorney General Dominic Grieve, the rebel amendment was passed by 321 v 299, a majority of 22.

It left shell-shocked Mrs May facing an all-or-nothing mighty showdown on Tuesday next week.

In a further hammer blow for the PM that left her authority hanging by a thread, the rebels also included an array of senior loyalists – such as ex-Cabinet ministers Damian Green, Sir Michael Fallon and Sir Oliver Letwin, as well as grandees Sir Nicholas Soames, Richard Benyon, Nick Boles and Ed Vaizey.

The centrist Tories insisted they were helping No10 block a No Deal outcome, which they say will devastate the economy.

Mrs May’s ex-de facto deputy until last year Mr Green told The Sun: “I wanted to leave options open for the Government and others to prevent No Deal, which would be disastrous”.

Former Fisheries minister Mr Benyon added: “I support the PMs deal but if it fails I want Parliament to have the option to prevent UK crashing out”.

But handing decision making powers to Parliament also means a simple majority of MPs could vote to;

Struggling to react to the blow, No10 refused to confirm whether Mr Grieve’s amendment would hand Parliament control of what happens next.

The PM’s official spokesman would only say that any MPs’ instruction would simply “reflect the will of the House”.

Senior Brexiteers called on No10 to stare down any majority of MPs that try to push Mrs May around.

Former Tory leader Iain Duncan-Smith insisted: “The Clerk of the Commons was clear that any such vote does not bind the Government.

“It will be a meaningless vote. The British people voted to leave and Parliament cannot frustrate that.”

But privately, senior No10 admitted that while any Commons motion would not be legally binding, it would be politically impossible to ignore the will of the House of Commons.

As Westminster was plunged into a frenzy after the shock vote, some loyal Tory MPs claimed the hammer blow could actually help Mrs May win round wavering Brexiteer Tory MPs to back her deal, fearing an even softer Brexit if it falls.

Backbench Eurosceptic Andrew Bridgen even accused No10 of conspiring with Mr Grieve to bring on the defeat.

Mr Bridgen told The Sun: “I am left highly suspicious after observing that the Government did not appear disappointed at all when the Grieve amendment went through.

“Now No10 can threaten Brexiteers with either her deal or Parliament saying no Brexit - but that’s a false choice.”

The defeat also sparked fresh calls from fervent Brexiteers for Mrs May to be ousted.

Another rebel Tory MP said: “This again proves it’s time for colleagues to get the letters in.

"Look what a disaster Theresa May is making of Brexit”.

The drama came just minutes before Theresa May fired the starting gun on the biggest show down in Parliament in decades.

A few minutes after the crippling defeat, the PM was forced to take to the Despatch Box to open the marathon five day debate on her deal.

After arguing for eight hours each day, MPs then vote on the 585 page Withdrawal Agreement and 26 page Political Declaration for a future trade deal at 7pm next Tuesday night.

Imploring the Commons to back her deal and save her Government, the PM surprised MPs by swiftly signalling she could make a fresh concession to Eurosceptics on the hated Irish backstop.

Separately Labour leader Jeremy Corbyn incensed Brexiteers by saying that reopening the negotiations couldn’t be ruled out.

And in incredible scenes, Tory MPs turned on each other as Boris Johnson labelled the PM’s deal a “national humiliation” and said it was “finely balanced” whether Britain would be better off staying in the EU.

In a passionate hour long address, the PM said she was aware of the fierce opposition to the so-called Irish ‘backstop’.

And she said: “I have listened to those concerns.

"I want us to consider how we could go further.

“And I will be meeting colleagues to find an acceptable solution.”

Government sources indicated this could involve giving MPs a vote on approving the activation of the insurance plan in 2020.

The PM had earlier warned that reopening the Withdrawal Agreement was impossible – and would give EU member states the chance to wrestle back wins from the UK in areas such as fisheries.

In a charged debate, Labour’s Yvette Cooper accused the PM of not being “straight” with the House on the failure to agree a comparable deal on security co-operation.

And DUP leader Nigel Dodds hit back at claims his party didn’t represent the pro-Remain feeling in Northern Ireland by saying he wasn’t afraid of another General Election.

Original Maastricht rebel Christopher Gill could be seen shouting “outrageous, outrageous” from the peers gallery as the PM spoke.

But in a passionate address, the PM urged the House to back her deal, reunite the country and put Britain on course for a brighter future.

She said: “This argument has gone on long enough corrosive to our politics and life depends on compromise.”

Defending the way she has handled the negotiations, the PM insisted that while she could have “banged on the table” and “faced criticism from all sides”, she had done what she believed was best for Britain.

She said: “I didn’t play to the gallery. I focused on getting a deal that honours the referendum, sets us on course for a bright future, and I did so through painstaking hard.

“Because I have never thought politics was simply about broadcasting your own opinions on the matter at hand.”

Defending her record, she added: “When the EU gave us a choice between off the shelf models, I won a bespoke deal.

“When in Salzburg the EU tried to insist on a backstop that carved out Northern Ireland from the rest of the UK I faced them down and they backed down.

"And right at the end when Spain tried to make a move on Gibraltar I stood firm and protected Gibraltar’s sovereignty.”

She said: “Don’t let anyone think there is a better deal to be won by shouting louder.

"Don’t imagine that if we vote this down a different deal is going to miraculously appear. The alternative is uncertainty and risk.

“I don’t say this deal is perfect it was never going to be, that’s the nature of a negotiation.

"Yes it is a compromise it speaks to the hopes and desires of our fellow citizens who voted to leave and those who voted to stay in.

“We will not bring our country together if we seek a relationship that gives everything to one side of the argument and nothing to the other.

“We should not let the search for the perfect Brexit prevent a good Brexit.”

But in a staggering sign of civil war in the Tory party, Conservative MPs turned on Boris Johnson as the former Foreign Secretary said no MP would “sincerely believe” is a good one.

In a barb at Brexit-backing members in the Cabinet he added that it appears “those sent out to support it know it is a democratic disaster”.

He also called for the Government to withhold the £39 billion divorce bill until the EU has agreed a trade deal. He stormed: “In Brussels they think they have us beat and our nerve will fail.

“They think we have got nothing left in our tank and that we want to do a deal at any price.

“Now is the time as we all think about this vote for us to show that they grossly underestimate this country."

But in a series of Tory counter-attacks ex-Minister Ed Vaizey stood up to insist he “sincerely” believed in Theresa May’s deal.

And fellow Brexiteer Roger Gale intervened to pan him for preferring “grievance to the solution”.

Backbenchers then howled with laughter when the big hitter said we may be 1-0 down against the EU but “we can win 2-0”.

The PM walked out 27 minutes into her arch enemy’s address.

With the PM listening on Boris ripped apart her deal and joked that it had achieved an “extraordinary thing” in bringing Remainers together with Leavers and “uniting the whole Johnson family”.

“This is a national humiliation that makes a mockery of Brexit.”

To heckling he summed up by warning people who voted Leave in 2016 voted for change, not an “endless transition or thinly disguised version of the status quo”.

He stormed: “It is a paint and plaster pseudo Brexit and beneath the camouflage we find the same old EU institutions the customs union & single market.

“The people of this country voted for freedom, they voted for independence and for a better Britain and for a country where politicians actually listen to what they have to say and if we try to cheat them now they will not forgive us.”

Labour leader Jeremy Corbyn had earlier accused Mrs May of putting the country over a barrel.

To the packed Chamber – which had earlier included Lib Dem MP Jo Swinson and her baby - he said: “Following the 2017 election, the Prime Minister could have attempted to build a consensus, recognising the new arithmetic of Parliament, and sought a deal that brought people together.

“Instead, just like her predecessor - who called a referendum without preparing for the eventuality of a Leave vote - the Prime Minister has seen these negotiations only as an exercise in the internal management of the Conservative Party.”

He added: “This Government is not taking back control, it is losing control.”