With the last results to come, Labour had won 410 of the 650 seats in the House of Commons, the most since Tony Blair’s 1997 landslide. It’s a remarkable turnaround in a single election cycle, but it was based on the backing of only 34% of voters. The Tories were on course for their worst ever performance on 117 seats. The populist Reform UK party led by Nigel Farage took chunks of the right-wing Conservative vote across the country, despite only getting four seats.

Starmer will now replace Sunak as prime minister on Friday, ending the Tories’ 14-year grip on power. The Labour leader has rebuilt Labour since his left-wing predecessor Jeremy Corbyn led the party to its worst performance in more than eight decades last time. When Starmer took over in 2020, it was assumed the Boris Johnson-led Tories would be in office for at least another decade.

But Johnson’s administration collapsed in scandal, and after Liz Truss’s disastrous 49-day premiership, Sunak was unable to move the polls in the Conservatives’ favor. The UK was set up for another political whiplash, and some big Tory names — Truss, Defense Secretary Grant Shapps and House of Commons leader Penny Mordaunt — were cast aside in the carnage.

The risk for Starmer is just as Johnson’s winning coalition of voters proved too broad and diverse to keep together, so Labour’s thumping win on Thursday was delivered from a broad but relatively shallow base. With votes still being counted, turnout for this election was on course for a 100-year low. 

That suggests a rejection of the Conservatives but also a lingering discontent over the traditional duopoly in British politics.

“I don’t promise you it will be easy,” Starmer said in his victory speech early Friday. “Changing a country’s not like flicking a switch.”

Starmer’s strategy was to capitalize on the Tory disarray by tacking to the political center ground where UK elections are traditionally won. He expelled Corbyn, and positioned Labour as the party of economic stability. Rachel Reeves, a former Bank of England economist who will be the UK’s first female Chancellor of the Exchequer, was key to Labour’s pitch to business.

Markets have been sanguine in the face of a projected Labour victory, sending gauges of volatility to near multi-year lows across currency and bond markets.

“A page turned, a new chapter started,” Reeves said after winning her Leeds West and Pudsey constituency. “We will not let you down. I will not let you down. And I can’t wait to get started.”

In the campaign, Labour was determined to avoid what’s known as stacking votes, which the party did under Corbyn and is lethal in Britain’s first-past-the-post election system. It worked, and Labour’s secured a massive majority from an overall vote share below historical norms for an incoming government.

Yet there’s unlikely to be the same Cool Britannia-driven euphoria that greeted Blair in 1997. Brexit still hurts the economy and Britons have endured a historic squeeze on living standards after the pandemic and Russia’s war in Ukraine.

Starmer’s manifesto fell short of what some progressives and especially his party’s left wanted. Labour’s argument is that a cost-of-living crisis and a Conservative Party determined to campaign on tax cuts made it impossible for Starmer and Reeves to be more ambitious.

But the strategy meant there were setbacks. Corbyn, as an independent, won his seat. Shadow cabinet members Jonathan Ashworth and Thangam Debbonaire lost, as left-wing and Muslim voters punished Labour for its stance on Gaza. Labour missed out on the chance to take former Tory leader Iain Duncan Smith’s seat, where an independent candidate split the progressive vote.

“While they have won the right to govern the country, they are not necessarily backed by a very high proportion of the country,” polling expert John Curtice said on the BBC. “They’ve still got an awful lot of people to win over during the course of their term of office.”

Labour’s resurgence, though, was just part of a major UK political restructuring. In seat after seat, Farage’s populist Reform UK party split the right-wing vote to devastating effect for the Tories. It also finished second to Labour in many areas. Speaking in Clacton, where Farage became an MP at his eighth attempt, the Reform leader made clear he’d soon turn his sights on Labour.

“This Labour government will be in trouble very, very quickly and we will now be targeting Labour votes.,” Farage said.

Even so, Labour’s victory ends a miserable time on the political sidelines as the Conservative government imposed years of austerity and led the UK out of the European Union, triggering political turmoil. Five years on from the Corbyn-led nadir in 2019, Labour is in a position almost nobody thought was possible.

In Scotland, Labour is again the dominant force, gaining from the Scottish National Party’s disarray since long-time leader Nicola Sturgeon stepped down. Past Labour governments have coincided with strong Scottish support, and Starmer’s party was on 37 with 4 left to declare. It had one last time.

And in England Labour could benefit as the Liberal Democrats, with whom Starmer’s party has common ground on public services, made huge inroads into the Tory heartlands. Maidenhead, ex-premier Theresa May’s seat before she stepped down at this election, was one of the areas to turn to Ed Davey’s party.

The Liberal Democrats were on 70 seats, up from 11 in 2019, with the final districts being counted.

Labour had gone into election day with a 20-point lead in Bloomberg’s UK poll of polls, a rolling 14-day average using data from 11 polling companies. The gap to the Tories had barely narrowed since Sunak caught his own party by surprise when he called a snap summer vote rather than wait until the autumn.

The outgoing prime minister is likely to face fierce recriminations for that decision, especially after an error-strewn campaign meant Tories were writing off their chances long before it ended. Sunak diverted resources to protect his seat, and he has said he will stay on as an MP even if he’s removed or steps down as Tory leader. But his party faces a fractious battle over how to recover.

“The British people have delivered a sobering verdict tonight,” Sunak said. “I take responsibility for the loss.”