As the Westminster meeting ended in a shouting match, angry Labour MPs rounded on Mr Corbyn, with one MP, ex-minister Ian Austin, telling him to “look in the mirror”.
Corbyn ally, shadow foreign secretary Emily Thornberry, was heard shouting at another critic of the Labour boss, Wes Streeting, after he said the party was being “driven off a cliff”.
Ex-minister Pat McFadden then told Mr Corbyn: “Our uselessness is emboldening the nationalist right wherever it exists.”
And the former chairman of the Parliamentary Labour Party (PLP), Lord Watts, told Mr Corbyn’s spin doctor Seumas Milne to his face that he was “a disgrace”.
More than two hours after the showdown at the PLP, Mr Corbyn launched a fightback on Twitter, appearing to laugh off the earlier row and urging his critics to stop “navel gazing”.
“Today, spirits in the Labour Party have run high, so I want to send a message to all party members,” he wrote, introducing a two-minute video.
In the video, appearing to chuckle, he begins: “Sometimes spirits in the Labour party can run high, today has been one of those days.”
He then continues: “That’s because we’re a passionate party. So I’m going to send a message to all party members. I want to make it absolutely clear, members are an asset. As a party we must do more to involve and empower them. “
And in a swipe at his critics, he says: “May’s local elections, to win we need unity, not navel gazing. My plea to all Labour party members, whether grassroots or in senior positions, is think of our people first. Think of our movement first. Think of the party first.”
But another Labour MP critical of Mr Corbyn, Neil Coyle, immediately responded on Twitter: writing: “When ‘navel gazing’ = ‘uncomfortable Copeland Qs’ & ‘more member engagement’ = absolutely no frontbench Brexit consultation with members…”
Earlier, the shouting and heckling inside committee room 14 in the Commons was so loud it could be heard clearly by journalists in a corridor outside the room.
After the meeting, Labour grandee Peter Mandelson told reporters the atmosphere in the party now was like that in 1985, when the Militant Tendency attempted to take over.
But when that was put to Lord Neil Kinnock, who as leader from 1983-92 fought bruising battles against the hard-left group, he told journalists: “No, it’s worse than that.”
After many Labour MPs left the meeting in a state of shock, a party official who was inside told Sky News: “It was brutal. It wasn’t pretty.”
And even Mr Milne, Mr Corbyn’s director of communications, told journalists: “There was a robust and open debate.”
On allegations of briefing against Labour’s deputy leader Tom Watson, Mr Milne said: “We did not encourage it.”
But an angry Lord Watts told Sky News: “I have told Seumas Milne he is a disgrace. He said I was abusing a member of staff, but it’s him who is abusing Labour Party members.”
The feuding between Corbyn allies and critics was triggered by a row over claims left-wing Momentum is plotting with the Unite union to seize control of the party.
The bust-up, at the weekly meeting of the Parliamentary Labour Party, followed a shadow cabinet away-day which ended with accusations of hostile briefing against Mr Watson.
He came under attack from pro-Corbyn sources after he told Sky News earlier: “It looks like a secret plan to take over the Labour Party to me, and I think it needs to be called out.
“I regard this as a battle for the future existence of the Labour Party. This is high stakes.”
The row at the PLP began when Mr Streeting, ex-minister John Spellar and veteran backbencher David Winnick asked Mr Corbyn who sanctioned the briefing against Mr Watson after the away-day.
The PLP chairman, left-wing Labour MP John Cryer, said the anti-Tom Watson briefing bore no relation to what happened.
Mr Watson looked visibly shaken as he left the PLP meeting. Asked if Labour was now in a state of civil war, a close ally told Sky News: “Not quite.”