British Prime Minister and Conservative leader Boris Johnson poses holding a fish with Conservative candidate for Great Grimsby Lia Nici (left) during a general election campaign visit to Grimsby Fish Market, northeast England on Monday. Britain will go to the polls on December 12. Photo: AFP

Britain went to the polls on Thursday to decide the future of Brexit in a snap pre-Christmas election aimed at ending years of political deadlock and bitter divisions over the country's ­European Union membership.

A decisive victory for Prime Minister Boris Johnson would most likely end Britain's 46-year involvement in the bloc next month.

But a win for the opposition could still reverse the Brexit process and give Britain its most leftist government in decades led by veteran socialist Jeremy Corbyn, who is committed to re-nationalization and massive public sector spending.

A windmill, a few pubs and a chip shop have all been hastily turned into polling stations across England, Scotland, Wales and Northern Ireland for what is widely seen as Britain's most important vote in a generation, and its third in less than five years.

Johnson, who has said the result is on a "knife edge," was the first party leader to vote in person, arriving at a central London polling station with his Jack Russell dog, Dilyn.

Opinion polls, which were almost unanimously wrong about Britain's last general election in 2017, show Johnson's ruling Conservative party in the lead, but possibly by a margin too small to form his own government.

Corbyn, who has had to brush off claims of indecision about his neutral stance on Brexit stance and claims of anti-­Semitism within his Labour Party flashed a thumbs up sign before casting his own ballot in north London.

Liberal Democrat leader Jo Swinson and Nicola Sturgeon of the Scottish National Party both voted soon afterward in Glasgow. 

All eyes initially were on the winter weather, with near-­freezing temperatures, rain and even snow in some parts ­potentially affecting voter turnout.

Up for grabs are all 650 seats in the British parliament, which has been deadlocked since the 2016 referendum on EU membership that saw a ­narrow majority vote to leave.

The first indication of the overall result will come in an exit poll at 22:00 GMT. The first actual result is due from around 23:00 GMT and the remainder will trickle in overnight.

A victory for Labour would make Corbyn the party's first prime minister since Gordon Brown in 2010 - and at 70, the oldest first-time premier since Viscount Palmerston in 1855.