A string of rebel Labour MPs have defied Jeremy Corbyn and backed the Brexit deal, in a boost to Boris Johnson’s hopes of forcing it through the Commons.

Up to nine of the party’s MPs are now expected to vote with the Conservatives, after Ronnie Campbell, Sarah Champion and Melanie Onn – who all represent Leave-backing seats – spoke out.

With at least 12 Conservative opponents of Theresa May’s deal announcing they would swing behind the prime minister’s reworked version, his chances of victory were growing.

However, an extraordinary procedural move by a cross-party group of MPs appeared set to delay the vote, which No 10 is determined to stage on Saturday afternoon.

Labour was locked in a civil war over the punishment to be meted out to its rebels, with Momentum founder Jon Lansman demanding they be expelled, while Mr Corbyn insisted they would not.

Mr Campbell, a North-East MP revealed he had been lobbied personally by the Labour leader not to back the deal – but insisted he would not bow to the pressure.

“I think you've got to grasp the straw yourself and get this sorted one way or another,” he said, adding: “I appreciate people being 100 per cent Remain but I'm 100 per cent Leave and always have been.”

Ms Champion, a south Yorkshire MP, described the deal on offer as “far from perfect”, in an email to a constituent, but claimed the alternative was now a no-deal Brexit.

“In these circumstances, and with the views of the majority of my constituents in mind, I confirm that I will vote for the deal,” she wrote.

Supreme Court verdict: Boris Johnson prorogation unlawful Show all 16 1 /16 Supreme Court verdict: Boris Johnson prorogation unlawful Supreme Court verdict: Boris Johnson prorogation unlawful The Supreme Court has ruled against Boris Johnson by declaring his government unlawfully shut down parliament for five weeks EPA Supreme Court verdict: Boris Johnson prorogation unlawful Lady Hale handed down the historic verdict, hailed by opposition MPs and anti-Brexit campaigners. She said all 11 judges were unanimous in deciding that the case is “justiciable”, so the government loses that part of the argument. “The court is bound to conclude therefore that the decision to advise Her Majesty to prorogue was unlawful because it had the effect of frustrating or preventing the ability of Parliament to carry out its constitutional functions.” EPA/Supreme Court Supreme Court verdict: Boris Johnson prorogation unlawful Gina Miller and her team react outside the Supreme Court are the verdict. She said: “Today is not a win for any individual or cause. It is a win for Parliamentary sovereignty, the separation of powers and independence of our British courts. Crucially, today’s ruling confirms that we are a nation governed by the rule of law, laws that everyone, even the Prime Minister, are subject to." PA Supreme Court verdict: Boris Johnson prorogation unlawful A person dressed as a caricature of British Prime Minister Boris Johnson in a prison uniform stands outside the Supreme Court AP Supreme Court verdict: Boris Johnson prorogation unlawful Labour leader Jeremy Corbyn called for Mr Johnson to “consider his position” following the landmark decision, while Lib Dem leader Jo Swinson said he was “not fit to be prime minister” Getty Supreme Court verdict: Boris Johnson prorogation unlawful Scottish National Party (SNP) Westminster leader Ian Blackford raises his arms as he comes outside. He said: "This is an absolutely stunning judgement by the Supreme Court today." He went on to say, "we all want to get back to work, and quite frankly, on the back of this, Boris Johnson must resign immediately." AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Crowds outside celebrated the verdict AP Supreme Court verdict: Boris Johnson prorogation unlawful Delegates at the Labour party conference applaud after hearing the news AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Speaker John Bercow said MPs must now “convene without delay” and confirmed the Commons would return at 11.30am on Wednesday AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Gina Miller said: "“As a result of this judgment, Parliament is open, it was never prorogued. I urge MPs to get back to work immediately.” AP Supreme Court verdict: Boris Johnson prorogation unlawful MPs Anna Soubry, Liz Saville Roberts and Caroline Lucas, together with SNP leader Ian Blackford, react. Green MP Caroline Lucas has said the Supreme Court’s decision is “just the start” Reuters Supreme Court verdict: Boris Johnson prorogation unlawful “The UK deserves a Prime Minister and a Government who act with honesty, integrity and in a manner consistent with our constitution, at all times." AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Anti-Brexit supporters react as they gather outside the Supreme Court in London, Tuesday, Sept. 24, 2019 as it makes it's decision on the legality of Prime Minister Boris Johnson's five-week suspension of Parliament. (AP Photo/Frank Augstein) Frank Augstein AP Supreme Court verdict: Boris Johnson prorogation unlawful The SNP’s Joanna Cherry QC says: “Boris Johnson’s position is untenable and he should have the guts to resign.” PA Supreme Court verdict: Boris Johnson prorogation unlawful epa07865617 Protesters react outside the Supreme Court after the result of a hearing on the prorogation of parliament, in London, Britain, 19 September 2019. The Supreme Court ruled that the suspension of parliament by British Prime Minister Boris Johnson was not lawful. EPA/NEIL HALL NEIL HALL EPA Supreme Court verdict: Boris Johnson prorogation unlawful Tom Tugendhat MP returned to the chamber in the House of Commons within minutes of the Supreme Court ruling PA

And Ms Onn, the Grimsby MP, wrote a joint article with a Conservative MP, arguing: “The risk of letting this final shot at a deal slip through our fingers is too great.

“Our collective hope rests on brave Labour MPs, and indeed others, who can see that.”

Two former Labour MPs now sitting as independents, Frank Field and Ian Austin, also confirmed they would side-by-side with the government.

It appeared likely that only one or two of the hardline European Research Group of hard Brexit-backing Tory MPs would hold out against the agreement.

But Philip Hammond, the former Tory chancellor, said he was still undecided, vowing not to be “duped into voting for a heavily camouflaged no-deal Brexit at the end of 2020”.

The warning followed the revelation, by John Baron, another Brexiteer, that he and others see backing the deal as the route to a crash-out in just 12 months’ time.

Mr Johnson, breaking off from efforts to win over waverers, urged MPs not to fail on “a very big moment for our country”.

“We have a choice, which is we have to consider how long we can delay and seem to frustrate what was a pretty clear democratic expression of the will of the people,” he told ITV News.