LONDON (REUTERS) - Voters went to the polls on Thursday (Dec 12) in an election that will pave the way for Brexit under Prime Minister Boris Johnson or propel Britain towards another referendum that could ultimately reverse the decision to leave the European Union (EU).

After failing to deliver Brexit by an Oct 31 deadline, Mr Johnson called the Dec 12 election to break what he cast as political paralysis that had thwarted Britain's departure and sapped confidence in the economy.

The face of the "Leave" campaign in the 2016 referendum, 55-year-old Johnson fought this election under the slogan of "Get Brexit Done", promising to end the deadlock and spend more on health, education and the police.

His main opponent, Labour leader Jeremy Corbyn, 70, promised higher public spending, nationalisation of key services, taxes on the wealthy and another referendum on Brexit.

All major opinion polls suggest Mr Johnson will win, though pollsters got the 2016 referendum wrong and their models predict outcomes ranging from a hung Parliament to the biggest Conservative landslide since the era of Margaret Thatcher.

Seven eve-of-election opinion polls published on Wednesday showed the Conservatives ahead of Labour by an average of nearly 10 points although Labour narrowed the gap in four of them.

"We could have a Conservative majority government which will get Brexit done and unleash Britain's potential," Mr Johnson told campaigners. "This election is our chance to end the gridlock but the result is on a knife-edge."

Mr Corbyn said the Conservatives were the party of "billionaires" while Labour represented the many. "You can vote for despair and vote for the dishonesty of this government, or you can vote Labour and get a government that can bring hope to the future," he said.

Polls opened at 0700 GMT (3pm Singapore time) and will close at 2200 GMT (6am on Friday, Singapore time) when an exit poll will give the first indications of the result.

Official results from the bulk of the United Kingdom's 650 different constituencies will begin to come in from 2300 GMT (7am on Friday, Singapore time) to 0500 GMT (1pm on Friday, Singapore time).

While Brexit framed the UK's first December election since 1923, the tortuous exit from the EU has variously fatigued, enthused and enraged voters while eroding loyalties to the two major parties.

BREXIT AND BORIS

A majority would allow Mr Johnson to lead the country out of the club it first joined in 1973, but Brexit would still be far from over. He faces the daunting task of negotiating a trade agreement with the EU in a self-imposed deadline of 11 months.

After Jan 31, Britain would enter a transition period during which it would negotiate a new relationship with the EU27. Mr Johnson has pledged to do that by the end of 2020.

Sterling markets are pricing in a Johnson win and the pound was up against the dollar and the euro in early trading on Thursday.

But two historic referendums - on Scottish independence in 2014 and Brexit in 2016 - and two national elections in 2015 and 2017 have delivered often unexpected results that ushered in political crises.

The election pits two of the most unconventional British politicians of recent years against each other. Both have been repeatedly written off by opponents and both offer starkly different visions for the world's fifth-largest economy.

Mr Johnson's pitch is Brexit but he shrank from anything more radical in a heavily choreographed campaign.

Mr Corbyn pitched what he calls a radical transformation for a country long wedded to free-market liberalism.

Mr Johnson, the New York-born former mayor of London, won the top job in July. His predecessor Theresa May resigned after failing to get parliamentary backing for her Brexit deal with the EU and then losing her party's majority in a snap election.

He defied critics by striking a new deal with the EU, but was unable to navigate the maze of a divided British Parliament and was defeated by opponents whom he portrayed as traitors subverting the will of the people.

The UK voted by 52 per cent against 48 per cent in 2016 to quit the EU.

But Parliament has been deadlocked since former prime minister May's failed bet on a 2017 snap election over how, when and even whether to leave.

MISSTEPS

Mr Corbyn, once an opponent of the EU who now says he would remain neutral if he was a prime minister overseeing another referendum, was repeatedly grilled over his Brexit plans. He pledged to overthrow a "rigged system" he said was run by billionaires and tax dodgers.

Both men have made missteps during the campaign.

Mr Johnson in one interview refused to look at a picture of a sick four-year-old boy forced to lie on the floor of a hospital and then inexplicably took the phone from a reporter and pocketed it. He later apologised.

Mr Corbyn, a veteran campaigner for Palestinian rights, repeatedly avoided apologising for what some party members, lawmakers and Jewish leaders say is his failure to tackle anti-Semitism from some elements within the party. He apologised eventually.

Mr Johnson's strategy was to breach Labour's so called "Red Wall" of seats across the Brexit-supporting areas of the Midlands and northern England, where he described his political opponents as the out-of-touch enemies of Brexit.

"If I'm honest with you, there's no choice," said voter Andrew Davis, from Kent in southern England. "I don't like any of the main candidates, so I'm struggling."