Today Labour MPs will vote on a motion of no confidence in Jeremy Corbyn after more than 40 members of his front bench resigned, demanding that he step down as party leader.
Mr Corbyn, who was heckled by his own MPs in the House of Commons yesterday, is now almost certain to face a formal challenge and a leadership contest which will be decided by an electoral college dominated by ordinary party members.
As members of the Parliamentary Labour Party denounced their leader at their weekly meeting in Westminster yesterday evening, his supporters gathered outside parliament.
Mr Corbyn has promised to stand again if there is a leadership contest, confident that he retains the support of the members who elected him by a landslide last year.
During last night's meeting, former home secretary Alan Johnson accused Mr Corbyn and his aides of sabotaging Labour's campaign against Brexit in the referendum.
Earlier, shadow business secretary Angela Eagle was close to tears as she spoke about her decision to resign from the front bench after calling on the leader to step down.
“It’s been an agonising decision, but I think it’s the first duty of every Labour leader to communicate with the electorate, and I think during the EU referendum, with just days to go to the vote, when we had a united party position, it emerged that half of our voters didn’t know what that was,” she told the BBC. “I think we are going to very possibly be facing a general election in the next four months and we can’t have our party led by someone who can’t get that kind of simple message across.”
Labour MPs, most have whom have been hostile to Mr Corbyn’s leadership from the start, have been emboldened to strike against him amid anecdotal evidence that some party members who voted for him last year now want him to go.
With a new Conservative prime minister likely to be in place by early September, Britain could face a general election before the end of the year and Labour MPs fear they could face an electoral catastrophe under Mr Corbyn’s leadership.
As Mr Corbyn scrambled to fill the vacancies in his front bench, some of Britain’s biggest unions issued public declarations of support for him.
"This is about democracy and respecting the Labour Party's democratic process. Jeremy has a strong mandate, and it's hugely disappointing that this is not being respected," said Tim Roache, head of the GMB union.
“Individual MPs of course have the right to choose whether to serve in shadow cabinet or not, but as long as he has the support of the membership, it is equally the right of the party leader to form that shadow cabinet and lead the party.”
Will Straw, a former Labour candidate who ran the hapless Britain Stronger in Europe campaign, yesterday sought to shift some of the blame for its failure on to Mr Corbyn. He said the Labour leader took a week's holiday in the middle of the campaign, instead of making a passionate Labour case for Britain's EU membership.
"Rather than finding imaginative ways for Labour to present a united front and get its message across to wavering supporters, Corbyn vetoed a planned event featuring all Labour's formers leaders," Mr Straw said.
"Rather than confronting concerns about immigration with Labour's values of contribution and reciprocity, Corbyn distanced himself from the manifesto commitment to restrict in-work benefits for new arrivals to this country and planned a trip to Turkey to talk about 'open borders'."
