Britain's two main parties are now in open conflict after a vote to leave the EU triggered an attempted "coup" in the main opposition Labour Party and a bitter leadership contest in the ruling Conservatives.
Both parties are reeling from the referendum result, when British voters rejected the arguments of experts and their leaders and decided to leave the European Union.
Prime Minister David Cameron has said he will resign, prompting a fierce battle to replace him, and several Labour lawmakers quit the party's top policy team to try to force their leader, Jeremy Corbyn, from office.
Scottish First Minister Nicola Sturgeon described the events as "a vacuum of leadership".
"I look on at what's happening in Westminster just now with a sense of utter despair on behalf of people across England and other parts of the UK as that vacuum of leadership both in the Tories and Labour develops," Sturgeon told the BBC.
She also suggested the Brexit vote could see the departure of Scotland, which voted to remain in the EU.
Cameron will stay on until October to try to help reassure the public and markets, but his resignation immediately after the vote has unsettled those who campaigned to leave the EU.
They say they will wait until a new eurosceptic leader is in place before triggering the process to leave the bloc as leading Conservatives jockey to take the mantle.
Former London mayor Boris Johnson, whose support for the leave camp galvanised the "Out" campaign, is favourite to replace Cameron but there is a group of pro-Cameron lawmakers looking for "anyone but Boris".
Eleven senior members of Britain's opposition Labour Party have withdrawn support for the leadership of Jeremy Corbyn, plunging the party into crisis.
On Saturday, Corbyn said he would resist any attempt to oust him following criticism by some Labour MPs that he had not done enough to convince millions of voters in the party's heartlands to back remaining in the EU.
He did not immediately respond to the resignations.
Britain is not due to hold a parliamentary election until 2020, but after Prime Minister David Cameron's resignation after losing the referendum, many expect that one could now be called earlier by his successor, putting pressure on Labour to present itself as a credible alternative.
The Labour leader sacked his foreign policy chief Hilary Benn early on Sunday after Benn said he had lost confidence in the ability of Corbyn, who is on the party's far left, to lead Labour.
Over the course of the day, Gloria de Piero, Heidi Alexander, Lucy Powell, Ian Murray, Kerry McCarthy, Vernon Coaker, Charles Falconer, Lilian Greenwood, Karl Turner and Seema Malhotra all announced they were stepping down from Corbyn's top team, known as the "shadow cabinet".
After a stinging election defeat for Labour last year, Corbyn won the leadership thanks to overwhelming support from grassroots members.
But he has struggled to win the backing of Labour's members of parliament, many of whom find themselves far closer to the centre ground than Corbyn.