Jeremy Corbyn was urged not to sack "highly-respected" colleagues who disagreed with him on key policies as he remained locked in talks over a contentious reshuffle of his top team.
The Labour leader was forced to cancel a planned meeting of the shadow cabinet after failing to conclude the shake-up more than 24 hours after discussions began with key aides and MPs.
His only confirmed move - sacking Michael Dugher as shadow culture secretary in a brief telephone call - sparked public dismay from a string of senior colleagues.
Mr Dugher said he had been removed for speaking out about the systematic "trashing" of the reputations of shadow cabinet colleagues briefed to the media to be in danger from a "revenge reshuffle".
Among the most high-profile mooted victims are shadow foreign secretary Hilary Benn - who backed air strikes on Syria and shadow defence secretary Maria Eagle who favours the renewal of the UK's nuclear deterrent.
Mr Benn, who had earlier returned to the leader's office for a second round of talks, appeared beside Mr Corbyn as he took a break from the tortuous wrangle to respond to David Cameron's Commons statement on the EU.
The Prime Minister mocked his opposite number for conducting "the longest reshuffle in history".
"Never mind how many Eagles we end up with," he said in reference to Maria and her twin sister, shadow business secretary Angela Eagle.
"I think you have all worked out you've got an albatross at the head of your party."
Labour's elected deputy leader Tom Watson led a chorus of senior figures bemoaning the "loss" of Mr Dugher, a close ally of former prime minister Gordon Brown, from the shadow cabinet.
He said he was a "rare politician - a talented working-class MP who hasn't lost his strong Yorkshire roots.
"Politicians with his ability and commitment can make a difference in any role. Labour's loss in the shadow cabinet will be compensated by Michael's free thought on the backbenches."
One shadow cabinet minister reportedly warned as many as eight colleagues could quit if Mr Benn, who angered Mr Corbyn with an impassioned Commons appeal for votes in favour of air strikes, was also removed from his role.
Mr Benn is due to speak for the Opposition later when the Commons discusses UK relations with Saudi Arabia.
MP Lisa Nandy, among those tipped to take the defence brief if Ms Eagle was ditched, denied rumours that she had been offered the role.
Mr Dugher, who was among those who last month backed UK military action in Syria after Mr Corbyn was forced to allow a free vote, had warned Mr Corbyn he would end up with a "politburo of seven" if he reshuffled left-wing allies into top jobs.
Revealing his sacking on Twitter, he updated his social media profile to mock the party leader.
"Sacked by Jeremy Corbyn for too much straight talking, honest politics," he wrote, in a direct echo of his party conference speech pledge.
The "real casualty" appeared to be the promise of an inclusive approach, he told Sky News.
"Good, hard-working, decent, loyal members of the shadow cabinet have had their reputations trashed in the newspapers because people in the employment of Jeremy have been giving those stories to the newspapers that all these people were going to be fired in some kind of revenge reshuffle," he said.
"Hopefully, touch wood, before we get to day three of what will be the longest reshuffle in history, we haven't had those mass sackings.
"I hope he can keep the party together and united and we can get on with our day job, which is getting rid of these Tories."
"People like Hilary and Maria are held in huge respect, not just in the shadow cabinet and the Parliamentary Labour Party but in the country as well."