Sir Keir Starmer is the UK's new prime minister, after his Labour Party swept to power in a landslide general election victory.
The Conservative Party suffered a huge collapse after a tumultuous 14 years in power, which saw five different prime ministers run the country.
Rishi Sunak - the outgoing PM - accepted responsibility for the result and apologised to defeated colleagues during a brief statement outside a rainy 10 Downing Street. He said he would resign as party leader in the coming weeks.
Earlier, in an impassioned victory speech, Sir Keir promised "national renewal" and vowed to put "country first, party second".
"We have earned the mandate to relight the fire," he told jubilant Labour activists in London. “Our task is nothing less than renewing the ideas that hold this country together.”
The result marks a stunning reversal from the 2019 election when Labour, led by the veteran left-wing politician Jeremy Corbyn, suffered its worst electoral defeat in almost a century.
On the other side, Robert Buckland, a former Conservative minister who lost his seat, described it as "electoral Armageddon" for the Tories.
It is the party's worst result in almost 200 years, with an ideological battle over its future direction expected to commence in the coming weeks.
It's been a long night of results. Here's what it all means.
Britain's House of Commons has 650 MPs, or members of parliament. Each of their "seats" represents an individual constituency - or area – somewhere in the country.
So far Labour has won 412 seats, while the Conservatives have slumped to just 120 and centrist Liberal Democrats have taken 71. Reform UK, a successor to the Brexit Party, is set to pick up four seats, as are the left-wing Green Party.
Labour's surge was partly aided by the collapse of the Scottish National Party (SNP). The party has been hit by a succession of controversies around its finances and fell to just nine seats overnight.
The expected 170-seat majority in the House of Commons for Labour is an enormous number but still short of the majority of 179 won by the party under Tony Blair in the 1997 election.
But for more perspective, the Conservatives' win in the 2019 election under Boris Johnson - seen as a very strong performance - saw them get a majority of 80 seats.
A reminder: If a party holds a majority, it means it doesn't need to rely on other parties to pass laws. The bigger the majority, the easier it is.
There were, however, a number of notable defeats for Labour to independent candidates campaigning on pro-Gaza tickets - especially in areas with large Muslim populations.
Labour has faced growing pressure over its stance to the conflict. In February, the party called for an immediate humanitarian ceasefire but critics said it was too slow to reach that position.
Centre-left parties in other Western countries were keeping a keen eye on the trend ahead of the poll, amid fear of a growing backlash from their own voters over their support for Israel.
As constituencies have declared their results live on television - with all candidates lined up next to each other on stage - there have been some major moments.
Perhaps the most notable was the defeat of Liz Truss. The former prime minister served just 49 days in Number 10 before being ousted by her party. She narrowly lost to Labour in the constituency of South West Norfolk, having previously held a huge 24,180 majority.
Jacob Rees-Mogg, the former Conservative business secretary and arch-Brexiteer, was one of the biggest names to suffer defeat. He lost his East Somerset and Hanham seat to Labour.
He told the BBC that he couldn't "blame anybody other than myself" for the loss but he took a "small silver lining" from the fact that the Conservatives would be "at least the official opposition" - a reference to fears they wouldn't even have that.
Grant Shapps, the defence secretary, looked rattled after losing his seat in southern England.
Leader of the House Penny Mordaunt, who ran against Rishi Sunak for the party leadership before he became prime minister, also lost her seat.
As the night wore on, a succession of other Conservative cabinet ministers also lost their seats, including: Education Secretary Gillian Keegan, Culture Secretary Lucy Frazer and Veterans Minister Johnny Mercer.
But Jeremy Hunt, who serves as chancellor - the UK equivalent of a finance minister - held on to his seat but with a much-reduced majority.
Mr Sunak also won his seat in Yorkshire with a comfortable majority of around 12,000 - but used his acceptance speech to concede and confirm his party had lost the election.
Labour also lost two big names of their own. Jonathan Ashworth and Thangam Debbonaire were both expected to be a part of Keir Starmer's incoming cabinet.
Jacob Rees Mogg and another candidate in his constituency. Neither won.
Things move pretty fast in British politics - there is very little time between an election result and the installation of the new prime minister.
Rishi Sunak moved out of 10 Downing Street on Friday morning - the British equivalent of the White House - and Sir Keir Starmer will be installed swiftly afterwards.
But there is a process. Mr Sunak offered his resignation to the King, and Sir Keir was formally invited by the monarch to form the next government in a meeting at Buckingham Palace.
He will then perform the traditional walk up Downing Street - watched by the world's media - before addressing the nation from the steps of Number 10.
After that he will be expected to invite top Labour MPs to Downing Street and appoint them to his new cabinet.
Speaking before he handed his resignation to the King, Mr Sunak wished his successor well.
"His successes will be all our successes, and I wish him and his family well," Mr Sunak said. "Whatever our disagreements in this campaign, he is a decent public spirited man who I respect."
He's fairly new to politics, relatively speaking.
Sir Keir started his professional life as a barrister in the 1990s, and was appointed the director of public prosecutions, the most senior criminal prosecutor in England and Wales, in 2008.
He was first elected in the Holborn and St Pancras constituency in north London in 2015, and took over leadership of Labour after the party's poor 2019 general election, pledging to start a "new era" after the left-wing leadership of Jeremy Corbyn.
Sir Keir was re-elected in the same constituency on Thursday, saying in his victory speech people were "ready for change" and promising an "end the politics of performance".
"The change begins right here because this is your democracy, your community, your future," he said. "You have voted. It's now time for us to deliver."
You can read Sir Keir's full profile here.
Nigel Farage after winning his seat.
This election's insurgent party was Reform UK, the right-wing successor to the Brexit Party and the UK Independence Party.
Nigel Farage, its leader, finally won a seat on his eighth attempt - but his party's initial projection of 13 seats fizzled to four. That's still better than UKIP and the Brexit Party ever did, and Mr Farage has been celebrating.
The party's share of the vote looks to be about 14%.
Reform drew controversy during the campaign over offensive statements made by some of its candidates and activists.
Mr Farage will be joined in the House of Commons by former Conservative party deputy chairman Lee Anderson, Reform founder Richard Tice and Rupert Lowe.
From their new perch in parliament, the party could seek to cause trouble for the Conservatives and pick off more voters from the party's remaining base.