Labour MPs are set to escalate the party's civil war by staging a no confidence vote in Jeremy Corbyn as they seek to oust their leader.
MPs followed two days of mass resignations by telling Corbyn he should stand down at a Westminster meeting on Monday night.
But the defiant Corbyn - blamed by some supporters for a lacklustre EU referendum campaign - refused to give in to the "corridor coup".
The party leader's aides said critics should launch a formal leadership challenge - believing he would win easily because of his overwhelming support among grassroots activists.
MPs will vote on the no confidence motion in a non-binding secret ballot later today - with the result expected at around 4pm.
At the acrimonious meeting of the Parliamentary Labour Party (PLP), Corbyn was urged to "do the decent thing".
The tone of the meeting was said to be "hostile" according to reporters from PA, with many MPs said to be close to tears and leadership contender Chuka Umunna describing it as "pretty catastrophic".
Former frontbencher John Woodcock is said to have had a stand up row with Corbyn's press spokesman.
The meeting can after more than 40 Labour MPs on his front bench and in his shadow ministerial team quit, saying they had no confidence in him as leader.
A large crowd of supporters turned out in Parliament Square on Monday to show solidarity for the Labour leader.
Corbyn appealed for "unity" and told the crowd: "Don't let the people who wish us ill divide us."
The Labour-supporting Daily Mirror has also called on him to quit.
The paper said filling dozens of vacancies with "inexperienced lightweights" was like "using a toothpick to prop up a collapsing skyscraper" and suggested Mr Corbyn's attempts at "clinging to power increasingly looks like an act of vanity".
It added: "A beleaguered Jeremy Corbyn should take a long hard look in the mirror, then do what is in the best interests of his party, working people and the country because, to be frank, it is increasingly hard to imagine him as a Labour prime minister on the steps of Downing Street."
The Opposition leader will continue to make appointments to his front bench team although it is unclear if every position will be filled.
Among the most senior figures to quit in Monday's wave of resignations was Angela Eagle, who, as shadow first secretary of state, deputised for the leader at Prime Minister's Questions.
The former shadow business secretary is among those tipped as a possible challenger to take on Corbyn.
(Sky News)