Pro-EU rock star Sir Bob Geldof has thrown his support behind the Liberal Democrats for the Richmond Park and North Kingston by-election, branding his "friend" Zac Goldsmith as a "political failure" on the eve of the 1 December vote.
"Worst of all of is that he's not only failed but betrayed the people of Richmond, who like the rest of London, voted overwhelmingly to stay in Europe," he said.
"How can Goldsmith represent the opinion of the people of Richmond in Parliament when he is the poster-boy for the Brexiteers and is urging the government daily on its catastrophic course?
"The fightback can begin in Richmond tomorrow; Zac has to go."
The intervention comes during the final full day of campaigning in the by-election. The vote was triggered in October when Goldsmith quit the House of Commons over the government's decision to back a third runway at Heathrow Airport.
The former Conservative MP is now contesting the constituency as an independent candidate, while the Tories, Greens and Ukip are not fighting the election.
But despite airport expansion being a major theme of the by-election, Liberal Democrat candidate Sarah Olney has also campaigned on a pro-EU platform, with a promise to vote down Article 50, the official mechanism to split from the EU, if she is elected.
Around 69% of Richmond-upon-Thames residents voted Remain at the 23 June referendum, while Goldsmith campaigned for a Brexit.
Former Deputy Prime Minister Nick Clegg told IBTimes UK that his party can "pull off an astonishing win" on Thursday.
"The reason why we have made up so much ground against Goldsmith is the fact that people locally don't like the fact that he's such a hard-line Brexiteer," the Liberal Democrat MP said.
"They want to send a signal to Theresa May and the Conservative government that they don't want this country pushed towards an economically self-harming Brexit."
But Goldsmith, who was injured in a "minor" car accident on Tuesday, is defending a majority of more than 23,000 votes from the 2015 general election. Jacob Rees-Mogg is one of the Conservative MPs who have endorsed Goldsmith.
"Zac is independent-minded and stands up for his constituents' interest," he told IBTimes UK. "He is a model of what an MP ought to be: he sticks to his beliefs even when it is not convenient to the hierarchy."
A BMG Research poll, of more than 500 voters in Richmond Park between 26 and 27 October, found that 56% (-2) of respondents backed Goldsmith, while 29% (+10) supported Olney.