UK Prime Minister David Cameron has called for Labour leader Jeremy Corbyn to stand down in the national interest saying: "For heaven's sake man, go."
Pressure on Mr Corbyn to resign has continued to intensify as he faced fresh resignations from the front bench — including one MP appointed to the shadow cabinet just two days ago.
During Prime Minister’s Questions, Mr Cameron waded into Labour’s misery, criticising Mr Corbyn’s role in the EU referendum campaign.
He said: “It might be in my party’s interest for him to sit there, it’s not in the national interest and I would say, for heaven’s sake man, go.”
Labour MP Harriet Harman said Mr Corbyn had “no right or mandate” to stay in office.
In a strongly-worded appeal to him to quit, the former deputy leader said: “Jeremy earned the right to take up the leadership of the party with a big majority. But he has failed and he has no right or mandate to stay in office despite his failure and take the party down with him.
“Leading the party is a privilege not a right. You earn the opportunity to lead by being elected, to lead the whole party, our voters, members, councillors and MPs.
“But winning the leadership election does not give you the right to continue in post if you fail. If Jeremy goes now, he will earn the respect and admiration of the party. If he stays he will be responsible for damage to the party on the gravest scale.
“No-one has the right to do that. Being leader of the Opposition is an immensely difficult task. Much harder than it looks. The starting point should be to support the leader and help them succeed. And that is what I have done over the past three decades and with six leaders through thick and thin.
“But I have no right to stand by and let our party collapse in disarray. That is what has happened under Jeremy and that has to stop. I urge Jeremy to stand down.”
Mr Corbyn will likely face a leadership election after a vote of no confidence, Labour MP and Shadow Chancellor John McDonnell has said.
However, MPs seeking to overthrow Corbyn must accept his leadership if he sees off the challenge, Mr McDonnell said as he called for an end to “nastiness”.
A defiant Mr Corbyn has vowed to fight on despite an overwhelming vote of no confidence by his own MPs, who declared their wish to see him gone by a margin of more than four to one.
Mr McDonnell said MPs had to “play by the rules”.
“It looks as though we will have a leadership election,” he conceded.
“All we are saying to Labour MPs is: play by the rules of our party and, if there is to be a democratic election, respect the decisions of our members.”
He told Sky News: “The most important thing at the moment is just calm down.
“Our country is facing some really serious risks at the moment and we have a job as MPs to try to come together to protect the people who might be affected, and they are largely the most vulnerable.
“We are all saddened that we are going through this because it is completely unnecessary and there has been some nastiness.”
Angela Eagle - the most senior member of the shadow cabinet to join a mass mutiny that has left Mr Corbyn struggling to find sufficient loyal members to form a new team - is widely tipped to be chosen to take him on in a formal contest.
While his Westminster colleagues are lined up against him, the leadership appears confident he still commands sufficient support among the wider membership to emerge victorious once again.
Crucially, he also appears to enjoy the support of trade union chiefs.
Mr Corbyn shocked the party when he battered established mainstream rivals in September on the back of an influx of left-wing activists, who have kept up a vocal support through the Momentum group.
Former foreign secretary Margaret Beckett warned there were "people around Jeremy who are prepared to see the Labour Party split rather than for him to go".
“That is anathema to everybody who thinks that we need to get rid of this Government and the damage that they are doing,” she told BBC Radio 4’s Today in an emotional appeal to the leader to step aside.
Dame Tessa Jowell told him it was "absolutely clear that your continued leadership is putting the Labour Party's future in jeopardy and denying millions of people in our country who so desperately need representation by a Labour government".
But Mr Corbyn dismissed the confidence vote as having "no constitutional legitimacy" and insisted he would not "betray" the 60 per cent of members and supporters who backed him to succeed Ed Miliband.
He will address a rally organised by the Momentum movement on Wednesday evening, with Public and Commercial Services union chief Mark Serwotka and Fire Brigades Union general secretary Matt Wrack also speaking in support of him.
Unite trade union general secretary Len McCluskey was among the first to rally to Mr Corbyn’s support after the no-confidence motion, accusing the MPs of “pointless posturing” and warning they would have to mount a full-blown leadership challenge if they wanted to oust him.