London - A surge in youth turnout fuelled by last year's shock Brexit vote played a pivotal role in stripping British Prime Minister Theresa May of her parliamentary majority, observers say.
An energising campaign by Labour's firebrand leader Jeremy Corbyn and simmering anger among many voters over uncertain plans to leave the European Union sent young Britons streaming to the ballot box.
Corbyn, a 68-year-old staunch leftist, harnessed popular anti-establishment sentiment to lead Labour to beat expectations and gain a clutch of seats in the House of Commons.
After a campaign marked by rallies that had the buoyant mood of music festivals, Corbyn said his success was built on hope for change.
"Politics isn't going back into the box where it was before," he told cheering supporters.
"What's happened is people have said they've had quite enough of austerity politics... and not giving our young people a chance they deserve in our society."
Some 56 percent of under-35s voted, according to an exit poll for NME magazine, which recently splashed Corbyn's face across its cover.
They showed overwhelming support for Labour, at 60 percent, with 36 percent of them being first-time voters, according to the survey among 1,354 voters.
Half cited Brexit as the "main factor" in their decision to cast a ballot.
While an official breakdown of voting patterns was still outstanding, official data showed a spike in both youth registrations ahead of the vote as well as turnout in districts with large numbers of younger voters on election day.
By contrast, only 45 percent of British voters aged 18 to 34 voted in 2015, compared with 84 percent of over-55s, which the OECD has called the biggest gap in the Western world.
A year later, a failure to drum up the youth vote was blamed for turning the Brexit referendum in Leave's favour.
"The movement of Remainers and young voters towards Labour explains why the Conservatives have lost their overall majority," political scientist John Curtice of the University of Strathclyde said.
Commentators said Corbyn had successfully presented himself as a true alternative to politics-as-usual.
They credited his idealism and folksy charisma, a savvy social media presence, and a parade of celebrity supporters including singer Lily Allen and comic Ricky Gervais with drumming up "Corbynmania" among the young.
He drew comparisons with US leftist senator Bernie Sanders' ability to whip up youth support in his ultimately unsuccessful presidential bid last year.
"Jeremy Corbyn appeals to a generation of young people who feel they have never known an honest, decent politician," wrote Rhiannon Lucy Cosslett in the Guardian.
"Last night's result shows youngsters have gained some revenge, with claims Theresa May's 'hard Brexit' mandate has been destroyed," pro-Labour tabloid Daily Mirror said.
The Economist cited a deep generational schism in Britain pitting uncertain young voters against baby boomers they accuse of selfishness and insincerity in politics.
Corbyn targeted specific youth issues in his campaign, including pledging to cut university tuition fees, lower the voting age and improving the employment rights of interns.
Failure to engage
Many young voters expressed surprise at their own ability to swing the election given that most opinion polls predicted a decisive May victory.
"I thought she was going to win it. I had heard a lot of people going for her, so I was like, Labour aren't going to get in now, but I'm pleased because Labour have a chance now," Jemma Bell, 23, told AFP in Wakefield, northern England.
"I know a lot of people that didn't vote last year and I think now they've realised that we could actually go to crap, in a sense, if they don't vote," she added, referring to last June's Brexit referendum.
Gus McKay, a 38-year-old Conservative voter at Euston station in central London, said he was "frustrated" May had failed to connect with younger voters.
"She didn't do enough to engage. Younger people want to engage more with their politicians. It looks like Corbyn did a better job."
By Deborah Cole