The Conservatives are heading for a majority of 86 in the General Election, the biggest majority since 1987, according to the exit poll tonight.
After polls closed in the first December General Election since 1923, Boris Johnson's party was predicted to get 368 seats compared with 191 for Labour. The Scottish National Party were said to be on course to get 55 seats and the Liberal Democrats 13.
The BBC/Sky/ITV poll suggested the Conservatives would have 42 seats more than the 326 needed for an absolute majority in the House of Commons. It would represent the best result for the Conservatives since 1987 and Labour's worst election result since 1935.
If the results turn out to be true, it will likely mean a swathe of Labour seats in Yorkshire and the Humber will be taken by the Tories. A YouGov poll this week said Labour would lose eight seats to the Conservatives in the region and one to the Liberal Democrats.
Reacting to the news, Labour's Shadow Chancellor John McDonnell said: "If it is anywhere near (the exit poll result) is is extremely disappointing.
Claiming that 2019's was a 'Brexit election', he said: "Brexit has dominated. We thought other issues would come through."
He added: "I hate to use the expression but I think voters did want to 'get it done'."
Asked if he and Jeremy Corbyn would resign if the results were true, he said: "We will see the results in the morning and then decisions will be made."
Polling booths opened across Britain this morning as voters headed to ballot boxes in what has been billed as the most important General Election in a generation.
Prime Minister Boris Johnson, who gambled his premiership by triggering the vote, has sought to focus on his pledge to "get Brexit done" throughout the campaign.
Labour leader Jeremy Corbyn, his rival in the race to Number 10, has instead tried to highlight his party's credentials on the health service and other domestic issues.
Mr Johnson arrived at Central Methodist Hall in Westminster at around 8.15am to cast his vote, bringing dog Dilyn along with him.
Labour Party leader Jeremy Corbyn was greeted by a small number of supporters as he arrived to cast his vote in Islington - and a protester dressed as Sesame Street character Elmo.
As the woman in fancy dress argued with security and police, Mr Corbyn said: "Hello guys, can we stop the arguments please."
He later posed for photographs with well-wishers outside the polling station.
It comes as the polls have narrowed in the final week of what has largely been a tame campaign - with few gaffes and many stage-managed visits.
On Monday Mr Johnson came under fire for his alleged lack of empathy when he pocketed a journalist's phone when asked to view a photograph of a four-year-old boy who was forced to sleep on a hospital floor.
The following day, however, Labour's campaign was rocked when a member of the shadow cabinet was revealed to have poured scorn on Mr Corbyn's election chances in a leaked recording.
A terror attack on London Bridge - which echoed a similar incident in the middle of the 2017 election - briefly disrupted the campaign, but quickly turned political as the Tories and Labour exchanged blows over how to deal with such threats.
The third General Election in less than five years has been largely dominated by the 2016 vote to leave the European Union - with Labour pledging to give voters another say in a second referendum, while the Tories have vowed to take the UK out of the EU next month.
A poll by The Daily Telegraph and Savanta ComRes, published on Wednesday night, placed the Tories five points ahead of Mr Corbyn's party - indicating the potential for a Conservative majority or a hung parliament.
But a separate poll by Kantar put the Tories on 44 per cent, Labour on 32 per cent and the Liberal Democrats on 13 per cent.
Voter turnout, however, could play a major role in the election outcome with rain, wind and chilly temperatures forecast for much of the country throughout Thursday.