But uncertainty remains with Labour’s recent surge in support; voter turnout will be key, says expert

Britain headed to the polls on Thursday, in an election in which turnout, particularly among the young, could play an important role in shaping the outcome. While polls still suggest a Conservative victory, their lead has narrowed sharply in recent weeks, putting at stake the validation of the government’s Brexit strategy that Prime Minister Theresa May had hoped to secure at the ballot box by further increasing her government’s majority.

“If I lose just six seats in this election, the government will lose its majority and Jeremy Corbyn will be sitting down with the Prime Ministers, Presidents and Chancellors of Europe in just a few days time,” said Theresa May in a statement published on Thursday morning.

When calling the election Ms. May had hoped that her party would be able to increase its 17-seat majority by both gaining seats from the U.K. Independence Party as well as benefit from divisions within the Labour. While the UKIP had done well in many Conservative strongholds in 2015, recent local elections had shown support for the party had collapsed as the Conservatives became the party of Brexit voters.

However, what it failed to count on was the strong campaign run by Labour leader Jeremy Corbyn, who has inspired those fed up with years of austerity under both Labour and Conservative governments, while at the same time bringing into the fold many within the party who had been sceptical about him at the start. The Conservatives have suffered a number of blows — with the terrorist attacks in London and Manchester raising questions about their track record on security and foreign policy, and a proposal on raising the costs of social care for the elderly potentially alienating those within one of its core constituencies. The result has been that Brexit has been less of a dominating issues that the Conservatives will have hoped for.

“I am very proud of our campaign,” said Mr. Corbyn, pictured out his local polling booth in London, after he had cast his ballot. “We cannot continue with these levels of inequality and injustice in our society. Labour will build a Britain that works for the many,” he said on Wednesday evening.

Comfortable lead

Still, polls give the Conservatives a comfortable lead. A Comres poll for the Independent newspaper late on Wednesday put the Conservatives at 10 points over Labour. The same poll puts the personal ratings of Ms. May at 48% and that of Mr. Corbyn at 39%. While Mr. Corbyn’s personal ratings have risen in recent weeks, Ms. May’s have fallen, putting into question the party’s strategy of focusing the campaign around her: the campaign often emphasised “Theresa May and her team”.

However, with polls in the U.K. failing to have predicted the outcome of the 2015 election and the results of last year’s Brexit vote, uncertainty remains, with voter turnout, potentially playing a significant role. “It could be very significant. The turnout among voters could well determine whether we have a clear Tory or a close Tory win — the group for which that is particularly uncertain is younger voters who are in general much more pro-Labour,” said polling expert Professor John Curtice of Strathclyde University.

Turnout at the 2015 election as 66.4%, though is expected to be higher this time, amid high levels of support for Labour and Mr. Corbyn personally.

The polls will also put to the test the significance of Brexit, and the fortunes of the Liberal Democrat Party, which has pegged its campaign around a commitment to holding a second referendum on the terms of the deal negotiated with the European Union. The ComRes poll has put support for the Liberal Democrats at 9%, suggesting that Britain will not see the trend witnessed in other parts of Europe (such as France), with a shift away from the mainstream parties.

Polls opened at 7 a.m. BST (11.30 a.m. IST), with many building up large queues as people prepared to cast their vote ahead of the voting day. Polls will close at 10 p.m., with the first exit polls coming out at that time potentially giving the clearest indication of where the results will be headed. The first constituencies will declare their results by just before 11 p.m., with some racing to be the first to be able to declare. The rest of the country will declare in the hours that follow into the morning. 46.9 million people are registered to vote across 650 constituencies across the country.