Brexit - Britain's two main political parties are in disarray after a referendum on European Union membership went against the wishes of their leaders to remain.
The resignation of nine members of the Labour Party's shadow cabinet, and sacking of another, is being described as an attempted coup to oust party leader Jeremy Corbyn.
Nine members of Labour's top team quit in protest at Jeremy Corbyn's leadership over the EU referendum. A tenth, Hilary Benn, was sacked after telling Mr Corbyn he had lost confidence in his ability to lead the party.
Mr Corbyn faces a vote of no confidence over claims his campaining to remain in the EU he was "lacklustre".
The Conservative Party faces a leadership battle of its own, with former London Mayor Boris Johnson and Home Secretary Theresa May emerging as the frontrunners to replace the outgoing prime minister David Cameron, who announced he would stand down on Friday shortly after losing the EU vote.
The first of the Labour Party's top team to resign was shadow health secretary Heidi Alexander, who said the country needed a credible opposition after voting to leave the European Union and that she did not believe party leader Mr Corbyn could provide it.
"As much as I respect you as a man of principle, I do not believe you have the capacity to shape the answers our country is demanding and I believe that if we are to form the next Government, a change of leadership is essential," Ms Alexander wrote to Mr Corbyn in a letter she posted on Twitter.
Mr Benn was sacked from the shadow cabinet amid reports he was encouraging ministers to resign should Mr Corbyn ignore a vote of no confidence.
"In a phone call to Jeremy I told him I had lost confidence in his ability to lead the party and he dismissed me," Mr Benn told the BBC.
The Labour party campaigned for Remain during the referendum, which saw the UK voting to leave the EU by 52 percent to 48 percent on Thursday.
Shadow chancellor John McDonnell said Mr Corbyn "worked himself to the ground" during the referendum campaign.
Labour MPs Dame Margaret Hodge and Ann Coffey submitted a motion of no confidence against Mr Corbyn - who campaigned on the losing Remain side - in a letter to the Parliamentary Labour Party (PLP) chairman John Cryer on Friday.
The motion has no formal constitutional force but calls for a discussion at the next PLP meeting on Monday. The chairman will decide whether it is debated. If accepted, a secret ballot of Labour MPs could be held on Tuesday.
Labour MPs reacted with criticism to Mr Corbyn's move to sack Mr Benn.
Meanwhile, Labour former culture secretary Ben Bradshaw urged the shadow cabinet to act swiftly to "save" the party.
He said: "The Labour shadow cabinet must now act to save the party and for the sake of the country. Otherwise we will never be forgiven."
On Saturday, Mr Corbyn vowed to fight off any leadership challenges and told one activist who heckled him as he attended a Pride march in London: "I did all I could."
The Labour leader vowed to ensure the party's voice was heard on workers' rights, protecting the environment and human rights in the negotiations on Britain's exit from the EU - and he suggested those negotiations should happen soon.
Quizzed afterwards about claims he had run a "half-hearted" campaign for a Remain vote, he said: "Two-thirds of Labour voters voted for Remain in response to our party's call for that."
He added: "There are some people in the Parliamentary Labour Party who would probably want somebody else being the leader of this party, they have made that abundantly clear in the past few days."
Mr Corbyn was confronted by Labour Party activist Tom Mauchline at the Pride event, who shouted: "It's your fault, Jeremy. When are you resigning? You need to resign."
However, an online petition on the website of campaign organisation 38 Degrees calling for Mr Corbyn to remain as leader has attracted more than 160,000 signatures from the general public.
In a joint statement, union leaders have also backed Mr Corbyn to continue as leader, saying the "last thing Labour needs is a manufactured leadership row of its own".
They called for Labour to "unite as a source of national stability" and challenge any attempt to use the referendum result to "introduce a more right-wing Conservative government by the backdoor".
Meanwhile, potential Tory leadership contender Boris Johnson has met with Conservative MPs Jake Berry and Ben Wallace at his home, and Justice Secretary Michael Gove.
The Sunday Times reports that Michael Gove has thrown his support behind Mr Johnson, while Cameron loyalists will favour the other frontrunner, Home Secretary Theresa May, who is expected to enter the leadership race in the coming days.
- BBC / Reuters