THE Liberal Democrats’ shock by-election victory was a rejection of a hard Brexit and could lead to an SNP-style bounce for the party, a jubilant Tim Farron has suggested.

The party leader claimed the overturning of a 23,000 Tory majority at Richmond Park in south west London was an "historic moment for the country".

Zac Goldsmith, who resigned his seat in protest at the UK Government’s decision to back Heathrow expansion, stood as an independent; the Tories did not field a candidate.

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Having lost earlier in the year in the London mayoral election, he was defeated in the by-election by Sarah Olney, who only joined the Lib Dems 18 months ago.

The by-election victor, who took 49.7 per cent of the vote, said the outcome had sent a "shockwave" through Downing Street and paved the way for Westminster to "override" the EU withdrawal referendum result. The Lib Dems believe there should be a second referendum on the final terms of the Brexit deal.

Mr Farron said: "Sarah is a reminder that populism does not automatically have to win. Those results, Brexit, Trump, the last general election, there was nothing inevitable about them. It is entirely possible for moderate progressive people to win through.”

While many believed, given Mr Goldsmith’s decision to spark the by-election, that it would be mainly fought on Heathrow expansion, the Lib Dem’s focused campaigning meant it was largely about the result of the EU referendum when most of the constituency backed Remain.

Mr Farron’s party poured enormous resources into the campaign, including a guest appearance on the stump from pop star and campaigner Bob Geldof.

Asked about previous false dawns, the Cumbrian MP told BBC Radio Four’s Today programme: “Let me just remind you that a referendum took place in Scotland in the autumn of 2014 when the SNP had six seats and because, rightly or wrongly, they caught the mood of the public we are in a situation where Scotland, wrongly, is now a one-party state.

“I’m not saying that’s how the UK should end up for the Lib Dems. I’m saying things can change dramatically quickly; British politics is very fluid. There’s a real need for a moderate electable, progressive party, which will take on the Tories and believe in a market economy and strong public services. If people think we can win, anything is possible,” he added.

But Tory backbencher Jacob Rees-Mogg suggested the Lib Dem by-election victory was not “a fundamental change in the political firmament,” noting how Mr Farron’s party now still had only nine MPs.

Pointing out how the by-election had been turned into a vote about Brexit and had taken place in a very strong Remain constituency, the Somerset MP said: “There’s understandably a disgruntlement amongst people who were strong pro-Remain that the country went against them.”

He praised Mr Goldsmith for “showing nobility” in standing by his word over Heathrow expansion and forcing the by-election.

Ms Olney’s victory means Theresa May’s working majority in the Commons has now been reduced to just 13. Asked for a reaction from the Prime Minister, her deputy spokesman declined to give one, saying it was a “long-standing convention” that No 10 did not comment on by-election results.

However, he did say: “The message from the British people was loud and clear on June 23 that there is a desire for us to leave the EU. The Government is getting on with delivering that."

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Asked whether the result might make Mrs May reconsider her decision not to hold a second EU referendum, the spokesman replied: "No."

The result saw Ms Olney poll 20,510 votes to Mr Goldsmith's 18,638, on a turnout of 41,367 or 53.6 per cent.

The 21.74 per cent swing to the Lib Dems from Mr Goldsmith topped the 19.3 per cent one they achieved from the Tories in the by-election at Witney, David Cameron’s old seat, which the Conservatives held onto.

Labour's Christian Wolmar lost his deposit as he trailed a distant third with 1,515 votes after the Greens backed the Lib Dem candidate. Ukip also stood aside to give Mr Goldsmith a clear run.