Pro-Remain parties in the United Kingdom surge in the European elections with the Liberal Democrats and Green Party both making big gains.

The anti-Brexit Lib Dems leapfrogged the Conservatives and Labour to win at least a dozen seats in the European Parliament.

The pro-EU Greens also increased their vote share.

Overall, explicitly pro-Remain parties are on course to win more votes than the pro-Leave Brexit Party.

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LONDON — Remain voters have surged to overtake anti-Brexit parties in the European elections in the UK, with the Liberal Democrats on course for their best ever result.

The Lib Dems came second in London and topped the poll in a number of councils where the Labour Party had won in the last European Parliament elections in 2014.

The party — which is campaigning to cancel the United Kingdom's exit from the European Union — came into the elections with just one representative in the European Parliament — but are set to end the night with at least 15.

Overall, explicitly pro-Remain parties are on course to win more votes than the pro-Leave Brexit Party.

Remain parties picked up votes from both Labour and the Conservatives, with the most eye-catching result of the night coming in Islington, north London, where the Lib Dems won despite Labour leader Jeremy Corbyn and Shadow Foreign Secretary Emily Thornberry both representing the borough in the UK parliament.

"The Lib Dems are back in business beating the Tories and Labour. We stuck to our guns with stopping Brexit in the same way we opposed the Iraq war," a Lib Dem source told Business Insider on Sunday evening.

A Lib Dem candidate in the European elections said: "Our Stop Brexit message has been heard by the public... We will use this momentum to continue our campaign to give the public a final say on any Brexit deal."

European elections projected seats (UK)

Brexit Party: 29 (+29)

Lib Dems: 16 (+15)

Labour: 10 (-10)

Green: 7 (+4)

Conservatives: 4 (-15)

SNP: 3 (+1)

UKIP: 0 (-24)

*BBC projected seat tally as of 01.00 AM (BST)

European elections projected vote share (UK)

Brexit Party: 32% (+32%)

Lib Dems: 20% (+13%)

Labour: 14% (-11%)

Green: 12% (+4%)

Conservatives: 9% (-15%)

SNP: 4% (+2%)

UKIP: 3% (-24%)

Change UK: 3%

*BBC projected seat share as of 01.00 AM (BST)

The Greens have also significantly increased their vote across the country and are set to add to the eight per cent which it won in 2014.

The Lib Dems also topped the polls in Remain-voting areas in the south east which it is targeting for the next general election, like Kingston upon Thames, Richmond Upon Thames, St Albans, Cambridge, Oxford, and Cheltenham.

The BBC in the early hours of Monday morning projected a second place nationwide finish for the Lib Dems.

Lib Dem leader Vince Cable said the results proved that the party was the "strongest Remain force in British politics."

He said: "Our clear, honest, unambiguous message has won us our best ever European election result, and pushed Corbyn's Labour into third place."

The Lib Dems' resurgence has largely come at the expense of the Labour Party.

Labour's policy of delivering Brexit and refusal to explicitly back a new referendum has led some Remainers to desert the party and back the Lib Dems and other anti-Brexit parties — including the Green Party.

Emily Thornberry, Labour's Shadow Foreign Secretary, criticised her party for being clear enough on Brexit, and told the BBC that Labour should have been more explicit in its support for a referendum and staying in the EU.

"We should have said quite simply that any deal that comes out of this government should be put to a confirmatory referendum and that Remain should be on the ballot paper and that Labour would campaign to Remain," she said.

"That's what we should have done."

Speaking in the early hours of Monday morning, Labour leader Corbyn said that his party would "have conversations" and "reflect" on the European election results.