In an extraordinary day for the Labour Party, the leadership crisis deepened even further as peace talks aimed at finding a way out of the deadlock were abandoned by deputy leader Tom Watson.
Watson's move left Labour leader Corbyn facing a leadership contest, with Angela Eagle as the potential challenger.
Here's how the chain of events unfolded:
1. Tom Watson abandons peace talks
The deputy leader of Labour announced that a planned meeting on Sunday with Len McCluskey and other leading Labour figures would not go ahead.
A crisis meeting had been expected to take place in Brighton on Sunday before the giant unions' conference in a final effort to break the deadlock over Corbyn's future.
Making a statement at the the Durham Miners' Gala, Watson said Corbyn's declaration that he would continue "come what may" meant "there is no realistic prospect of reaching a compromise" over his future.
"It is with regret and profound sadness that I have concluded there is little to be achieved by pursuing wider conversations with our union affiliates at this time," Watson said.
"The Labour Party was founded with the explicit aim of pursuing the parliamentary path to socialism. Every Labour leader needs to command the support of their MPs in the Parliamentary Labour Party (PLP), as well as party members, in order to achieve that.
"It is clear to all that Jeremy has lost the support of the PLP, with little prospect of regaining it."
2. Angela Eagle revealed her plan to announce her bid for leadership on Monday
Eagle, who resigned as shadow business secretary last week, said leader Jeremy Corbyn had failed "to lead an organised and effective" party.
She thanked Watson, Parliamentary Labour Party chairman John Cryer, chief whip Rosie Winterton and the union movement for trying "to find a solution to the impasse Labour faces with a leader who has failed to fulfil his first and foremost duty, that is to lead an organised and effective Parliamentary Labour Party that can both hold the Government to account and demonstrate we are ready to form a government in the event of a general election".
She added: "On Monday morning I will announce my candidature for leader of the Labour Party. I will explain my vision for the country and the difference a strong Labour Party can make."
3. Jeremy Corbyn vowed to fight a leadership challenge from Eagle
The Labour leader's spokesman said it was "disappointing" that his deputy Tom Watson had walked away from the union-brokered talks which were attempting to end the impasse between the embattled Corbyn and his MPs.
A spokesman for the party leader said: "Jeremy Corbyn has reached out to Labour MPs and made clear he wants to work with them to carry out his role as elected leader of the party.
"Jeremy regards the talks with trade union leaders as a vehicle to bring people together, and it is disappointing that some have walked away from them.
"Jeremy is committed to fulfilling all his responsibilities as democratically elected leader and will not betray the hundreds of thousands of people who elected him for a different direction for the Labour Party and a different kind of politics.
"He continues to be fully committed to working with the Parliamentary Labour Party and is ready to talk with as many people as necessary to assist that process, discussing policy initiatives and listening to ideas.
"He will remain leader of the Labour Party and will contest any leadership challenge if one is mounted."
4. Len McCluskey condemned Watson over 'act of sabotage'
The general secretary of Unite angrily attacked a decision by Tom Watson to call off a meeting over the Labour leadership as an "act of sabotage".
He said: "I am dismayed at the statement issued by Tom Watson announcing his withdrawal from talks aimed at resolving the crisis in the Labour Party.
"Extraordinarily I received no notice of this statement before it was issued. I had made arrangements for a meeting of trade union leaders, Tom Watson and representatives of the PLP and the party leader for tomorrow, arrangements requested by Tom Watson and his colleagues, specifically for Mr Watson's convenience.
"In that context, when the possibility of a workable plan had never seemed closer, Tom Watson's actions today can only look like an act of sabotage fraught with peril for the future of the Labour Party.
However, McCluskey added that Corbyn's resignation was never on the table.
"I must clarify one point in Tom Watson's statement - I made it absolutely clear from the outset of these discussions that Jeremy Corbyn's resignation as the leader was not on the agenda.
"Mr Watson knew that, and it is entirely wrong to suggest that any public statement by Jeremy represented any change in the situation.
"This is a deeply disingenuous manoeuvre."