Almost half of the UK's shadow cabinet plans to resign in order to force Labour leader Jeremy Corbyn to step down, according to media reports.
This comes shortly after Corbyn dismissed his shadow foreign minister, Hilary Benn, following revelations he was orchestrating a coup against the Labour leader.
On Sunday, Health Secretary Heidi Alexander became the first cabinet member to announce her resignation.
She tweeted, "It is with a heavy heart that I have this morning resigned from the shadow cabinet.”
Corbyn faces a vote of no confidence over his handling of Thursday's EU referendum, which saw Britain breaking away from the European Union by a 52-48 margin.
Hours after the referendum, two lawmakers submitted a motion of no confidence in Corbyn and other MPs also called for his resignation.
Corbyn said he would resist any attempt to oust him.
Members of the shadow cabinet said they were now writing their resignation letters after Alexander stepped down, according to the Guardian.
Before Benn was sacked, he had called fellow MPs over the weekend to suggest that he would ask Corbyn to resign if there was significant support for a move against him.
Benn had also asked colleagues to resign if Corbyn ignored their request.
He said there was concern about Corbyn's “leadership and his ability to win an election,” adding, “There is no confidence to win the next election if Jeremy continues as leader.”
“In a phone call to Jeremy I told him I had lost confidence in his ability to lead the party and he dismissed me,” he said.