LONDON   -   British voters are heading to the polls Thursday for a crucial general election that is being seen as a referendum on 14 years of Conservative rule.

The snap vote, called by Prime Minister Rishi Sunak, is being held months earlier than necessary and caught much of his party by surprise.

The opposition Labour party suffered its worst defeat since 1935 in the last general election, but has since rebuilt itself under the leadership of Keir Starmer. Thursday’s vote follows a six-week campaign in which all major parties have scoured the country in search of votes.

Much of the debate has revolved around the economy, the cost of living, the state of Britain’s public services, and tax and immigration.

Largely absent from the debate, however, has been Britain’s relationship with the European Union, which it left in 2020 after a referendum four years earlier.

Britain has had three Conservative prime ministers since the last general election in 2019, which Boris Johnson won by a landslide.

But after much of the country and his party soured on Johnson, Conservative party members voted in 2022 to replace him with Liz Truss, who became the shortest-serving prime minister in British history. Conservative Members of Parliament (MPs) then voted to replace her with Sunak.

During the campaign, Nigel Farage – one of the most prominent champions of Brexit – announced his return to frontline politics to lead the nascent hard-right Reform UK party.

Sunak, Starmer, Farage and the heads of all other major parties are expected to make appearances at their own local polling stations throughout the day.

Around 46.5 million Brits are eligible to vote in the election. They are casting their ballots in 650 separate constituencies across the nations of England, Wales, Scotland and Northern Ireland, with 326 seats required for a party to form a majority government.

News outlets are barred from reporting anything that could influence voters while polls are opened. An exit poll from British broadcasters will project the seat totals are soon as polls shut at 10 p.m. local time (5 p.m. ET), and counting will take place throughout the night and into Friday morning.

On Thursday, there are 650 parliamentary seats up for grabs, each of which will be occupied by one Member of Parliament (MP) in the House of Commons. For any single party to win an outright majority in the Commons, it would need to win at least 326 seats — over half of those available.

Any party that does that gets to form the next government, with its leader becoming the prime minister.

Parliament was formally dissolved on May 30 when Sunak called the election, as is procedure, but prior to that, Sunak’s long-ruling Conservative Party held an outright majority of 345 seats, giving it significant power to set the policy agenda.

The U.K. has what is called a first-past-the-post system, which means voters receive a ballot paper with a list of candidates from different parties and select only one of their choice.

Voting begins in the U.K. general election on Thursday morning, and most constituency results are expected by early Friday morning, although this may take longer in some more rural parts of the country — particularly if the vote tally is close or subject to a recount.

There is usually an early indicator of the overall results of a U.K. general election as a joint exit poll is released by British broadcasters Sky News, ITV and CBS News’ partner network BBC News immediately after the polls close.  The exit poll generally provides an accurate representation of the final results and can be expected by about 10 p.m. on Thursday local time (5 p.m. Eastern).

U.K. election predictions and polling data

Polls and political analysts have predicted for many weeks that Labour will sweep to a landslide majority in Parliament. If the latest polling data proves accurate, Sunak’s 18-month tenure will end and Britons will wake up Friday morning to a new party in charge of the country for the first time in 14 years.