LONDON — The U.K. heads to the ballot box on Thursday, as the incumbent Conservative Party seeks to defy months of polls that suggest it will suffer a historic defeat at the hands of the center-left Labour Party.

Prime Minister Rishi Sunak announced the vote six weeks ago, taking politicians and the public alike by surprise. Most had expected the election to take place later in the year, giving more time for the recent decline in inflation and anticipated reduction in interest rates to hit voters’ wallets.

A number of smaller parties are vying to win seats in the 650-member House of Commons, the U.K.’s lower house of parliament, including the Liberal Democrats, Greens, Scottish National Party, Plaid Cymru, the Democratic Unionist Party and Nigel Farage’s Reform UK. Votes will be cast across England, Scotland, Wales and Northern Ireland.

Within the U.K. political system, a party increasing its share of the popular vote does not necessarily translate to winning more parliamentary seats — and it is all but guaranteed that either the Conservatives or Labour, led by Keir Starmer, will receive the reins of power. That could either be through winning an absolute majority or by forming a coalition government.

Convention says the leader of the party with the most seats in the Commons becomes prime minister

Political surveys have for nearly two years pointed to a resounding Labour victory, even though the party will require a historic gain of nearly 13% in the national vote to win even a narrow parliamentary majority, according to Hannah Bunting, lecturer in quantitative British politics at the University of Exeter. That would be a bigger swing than the one achieved by Labour’s Tony Blair over John Major in 1997.

A strong Labour lead was reinforced in a major aggregate poll released by YouGov earlier this week.

However, politicos and Labour itself caution that no outcome is guaranteed and that the polling can be inaccurate. More than 100 seats are considered very close to call, including those currently held by high-profile Conservatives, including Finance Minister Jeremy Hunt and Sunak himself.

The Thursday ballot is the first U.K. general election since 2019, when then-Conservative leader Boris Johnson clinched the party’s biggest majority win since 1987 over Jeremy Corbyn’s Labour. That was on a platform promising to complete the “Brexit” process of leaving the European Union, which had become mired in a political gridlock.

Johnson’s administration was then marked by several public scandals, including the “Partygate” case in which senior politicians broke lockdown rules during the Covid-19 pandemic, leading to his reluctant resignation in July 2022.

He was succeeded by Liz Truss, who lasted just 44 days in office before resigning over the so-called mini-budget crisis, which rocked financial markets.

Sunak, a former finance minister for the Conservative Party, has since overseen a period of relative political stability; but one in which the country has been grappling with a severe cost of living crisis and sluggish economic growth.

The legacy of 14 years of Conservative rule — with the party winning power through a coalition arrangement under David Cameron in 2010 — has been a key theme on the campaign trail.

Sunak and Starmer have sought to convince the public that their party can address critical issues spanning housing, the National Health Service and defense.

Sunak claimed during a debate in early June that Labour’s policies would lead to a £2,000 ($2,553.73) tax rise for “every working family” over the course of the next parliament. Starmer said the figure was “made-up,” while the party has laid out tax increases targeting only specific groups.

The public has from 7 a.m. to 10 p.m. local time to cast a vote for their local parliamentary candidate, shortly after which a closely-watched exit poll will be released.

Ballots will be counted overnight, with a result expected out on Friday morning.