Theresa May was battling for survival as Britain's prime minister after her gamble to call an early election backfired spectacularly on Friday as the UK headed for a hung parliament, with her Conservative Party on the verge of losing its parliamentary majority and May facing calls to resign.
The prospect of a hung parliament casts doubt over the government's make-up as well as the direction and timing of negotiations on leaving the European Union.
May opted for a snap election seeking to boost her parliamentary majority and strengthen her hand in the Brexit talks due to begin in just 10 days. Instead, her Conservative Party was on course to win 318 seats, down from the 330 she held at the start of the campaign and short of the 326 seats she needs for an overall majority.
Jeremy Corbyn's Labour Party was forecast to win 262 seats - an unexpected gain of dozens of seats under the far-left leader. The outcome gave him at least a chance, albeit a remote one, of becoming prime minister - something virtually no one had thought possible before Thursday's vote.
The outcome - an astonishing turn following a campaign that began with predictions that May would win in a historic landslide - immediately raised questions even among her fellow Tories about whether she could maintain her hold on 10 Downing Street.
It also threw into disarray the country's plans for leaving the European Union, threatening to render Britain rudderless just days before talks were to begin with European leaders over the terms of the nation's exit.
May has signalled that she will try to form a government to ensure some stability. The BBC reported that May intends to try and stay on as prime minister, and the most obvious route to continued Conservative Party rule would be to form an alliance with Northern Ireland's pro-Brexit Democratic Unionist Party.
Yet, with calls for her resignation already coming from her Tory party, it's far from clear whether she will be able to hold on and lead the UK into talks with the EU that will determine the country's future prosperity.
''At this time, more than anything else, this country needs a period of stability,'' May said in her electoral district of Maidenhead, west of London, her voice at times shaking. ''If, as the indications have shown, the Conservative Party has won the most votes and the most seats, it will be incumbent on us to ensure that period of stability and that's what we will do.''
The pound tumbled the most since October as investors were confronted with another spasm of political turmoil less than a year after Britain voted to quit the EU, its biggest trading partner.
May called the election seven weeks ago expecting to win a landslide, but instead managed to squander the commanding lead she enjoyed at the outset with a gaffe-prone campaign that focused in large part on her vision of a post-Brexit Britain outside the EU's single market. That ''extreme version of Brexit'' was rejected by voters in Thursday's election, according to Keir Starmer, the Labour Party's Brexit spokesman.
''I think hard Brexit went in the rubbish bin tonight,'' said George Osborne, the former chancellor of the exchequer whom May sacked after he played a leading role in the campaign to remain in the EU.
The pound dropped as much as 2.1 per cent and was trading at $1.2707 at 8:26 am in London.
''Politics has changed and politics isn't going back into the box where it was before - because what's happened is people have said they've had quite enough of austerity politics,'' Corbyn said after retaining his seat in north London, and called on May to quit.
''The prime minister called the election because she wanted a mandate, the mandate she's got is lost Conservative seats, lost votes, lost support,'' the Labour leader said. ''That's enough to go.''
The Scottish National Party is on course for 35 seats, down from 56 in 2015, and the Liberal Democrats may get 13, up from 8, the forecast showed. In Northern Ireland, the Democratic Unionist Party won 10 seats and the Irish Republican Party Sinn Fein won 7 seats.
One of the biggest surprises of the night came when the constituency of Canterbury, which has been held by the Conservatives for more than a century, fell to Labour. Ben Gummer, who co-wrote the Conservative manifesto and was tipped to become Brexit secretary after the election, lost his seat in Ipswich, eastern England. Former Deputy Prime Minister Nick Clegg and Alex Salmond, the former SNP leader, were also defeated.
Whether or not May manages to stay on, her party's best option looks like governing with the support of the Democratic Unionist Party.
''We need to wait and see what decision Theresa May takes on her own future and then we'll reflect on it going forward,'' DUP leader Arlene Foster told Sky News. ''What we want to see is a workable plan to leave the European Union.''