A shock poll has put the Liberal Democrats in first place in London for the upcoming European Parliament elections in May.

The poll, conducted by YouGov, puts the Lib Dems on 23% in London, compared to 18% for Labour and 15% for the Conservatives. The Green Party received a mere 14%, dealing significant damage to their spurious claim to be the strongest pro-European party in the upcoming elections – lagging nearly 10% behind the Liberal Democrats.

The poll was based on a hypothetical question, asking how people would vote if Labour came out in favour of a customs union Brexit. But significantly, this is their position, with rumours that the Labour negotiating team is trying to agree on precisely that with the Prime Minister. Furthermore, their 2017 manifesto pledged Brexit, and an end to freedom of movement. As such, the hypothetical is more real than initially thought, leading some commentators to state that the Liberal Democrats are in fact in the lead in London.

This is a significant breakthrough for the pro-EU party, who have led the fight against Brexit since 2016, when Tim Farron was the first major party leader to suggest a People’s Vote.

With the d’Hondt system of proportional representation meaning that split votes are hypothetically possible, and with the Green Party and Change UK both having rejected Lib Dem overtures to create a so-called “Remain Alliance”, pro-EU voters are looking for the strongest party to rally around. This latest poll is significant evidence that that party is the Liberal Democrats, who, coupled with their 100,000 strong membership and significant progress in elections since 2016, look likely to be the party of choice for anti-Brexit voters.

“It’s clear now more than ever that the Liberal Democrats are the best-placed pro-EU party to face down Nigel Farage and his Brexit extremists,” said one Liberal Democrat source. “Labour are pro-Brexit, and the Greens and CUK are nowhere to be seen. Only a vote for the Lib Dems will show the government that Remainers mean business.”