MPs including Michael Gove and Theresa May put themselves forward to replace David Cameron.
Thousands have protested in London against British voters’ decision last week to leave the European Union, which has left the country deeply polarised.
Most protesters who gathered on Saturday were young adults, and many were draped in EU flags, while others waved banners in support of continued British membership in the bloc.
Marching through the Westminster political district, they chanted: “What do we want to do? Stay in the EU.”
“I was genuinely stunned on the morning after the vote,” Nathaniel Samson, a 25-year-old marcher from Hertfordshire, north of London, told the Reuters news agency.
“I feel deeply uncertain about my future,” he added. “I’m on the march to voice my discontentment. I am accepting the result, but it’s to show that we won’t accept it quietly.”
London voted 60 percent in favour of remaining in the EU in last Thursday’s referendum, with younger voters widely backing staying in the bloc, but 52 percent of Britons overall cast ballots in support of leaving.
Al Jazeera’s Barnaby Phillips, reporting from London, said “some people are calling for a second referendum at such a time in the future”, while others say “there should be a general election later this year”.
Although parliament has the final say on the exit, our correspondent said that Britain “would enter very uncharted and potentially unstable territory” if the referendum’s results were not respected.
The vote to leave has prompted a battle within the ruling Conservative party over the successor of Prime Minister David Cameron who said he would resign following the referendum’s result.
The campaign to leave the EU promised to halt immigration, blaming much of the country’s economic woes on foreigners coming to live in the UK.
Following the referendum, the UK saw an increase in racist attacks targeting Muslims, Southeast Asians, Poles and Romanians, among others.
Speaking to Al Jazeera’s UpFront, London mayor Sadiq Khan said: “Those responsible for orchestrating [the Leave] campaign need to now explain this rise in racial violence, this rise in racial abuse [and] this rise in racial tension.
The main opposition Labour Party has also turned on itself, with most of its members in parliament having voted to withdraw support for leader Jeremy Corbyn after what they saw as his lacklustre contribution to the referendum campaign.
Dozens have resigned en masse from Labour’s leadership bench.
“Corbyn didn’t make a convincing case for remaining in the EU, and he deserves some of the blame for that,” Oz Katerji, a journalist and political analyst, told Al Jazeera by telephone.
There has been speculation that a number of Labour MPs, among them Angela Eagle, may challenge his leadership – but Corbyn remains adamant that he will not step down following a vote of no confidence by MPs.
The Labour leader still enjoys widespread support among party members and supporters.
A majority of new Labour members who have joined since May 2015 disapprove of Labour MPs’ efforts to oust Corbyn.
At least 55 percent of new members support deselecting Labour MPs who consistently challenge the leadership, according to a new study by academics from the Queen Mary University of London and Sussex University.
At least 60,000 people have joined Labour in the past week amid the ongoing attempts to oust Corbyn, reported The Independent.
A new survey conducted by the YouGov polling group found that there is not enough support for Corbyn’s challengers to topple him.