Conservatives hold Cameron's old seat in Witney by-election

The Tories have held David Cameron’s Witney constituency in a by-election, but with a majority slashed from more than 25,000 to just 5,702 in a dramatic Liberal Democrat comeback.

The result, on Theresa May's 100th day as Prime Minister, is a warning to the Conservatives that they are vulnerable to a potential backlash from voters against the Government's handling of Brexit negotiations.

The Lib Dems snatched second place from Labour, who were pushed into third place in a result that will re-open criticism of Jeremy Corbyn's leadership.

Veteran Green Party activist Larry Sanders, brother of former US presidential Bernie, came fourth for the Greens and pushed UKIP into fifth place.

Jubilant Liberal Democrats claimed their party is "back in business".

Leader Tim Farron, who made five visits to the constituency during the campaign, will visit again later on Friday to congratulate his party's candidate, local councillor Liz Leffman.

The new MP is Robert Courts, 37, a barrister and deputy leader of West Oxfordshire council. He backed Leave in the EU referendum and supports Theresa May's controversial policy of bringing back grammar schools.

In his acceptance speech, Mr Courts paid tribute to his predecessor as a "great Prime Minster and a brilliant MP for West Oxfordshire".

He also said he looked forward to working with Prime Minister Theresa May and the Government to "help deliver a country that works for everyone and builds on the achievements that we have made since 2010."

His 17,313 votes amounted to 45% of the votes cast, a slump from the 60% won by Mr Cameron when he held the seat in the general election last year.

The Lib Dems' Liz Leffman won 11,611 votes, Labour's Duncan Enright 5,765, Mr Sanders 1,363 and UKIP's Dickie Bird was just behind on 1,354 votes.

Turnout was 47%, down from the 73% in the general election, but fairly typical for a mid-term by-election where one party is defending a big majority.

Despite the scale of the majority won by the former Prime Minister in 2015, all the main parties fought this by-election campaign as if the seat was a marginal.

Mr Cameron joined his successor, Mrs May, in campaigning for Mr Courts in the constituency at the weekend and Jeremy Corbyn spoke to a packed audience in Witney on Saturday, urging Labour supporters to "paint the town red".

But it was the Lib Dems, desperate to trigger a "Brexit backlash" in the by-election after the EU referendum, who put the biggest effort into the campaign and poured the most resources into it. And it paid off handsomely.

In a constituency that voted by 54% to 46% in favour of Remain in the EU referendum on June 23, the LibDems fought a strongly pro-EU anti-Brexit campaign, which appeared to resonate with many voters in this affluent Oxfordshire constituency.

Former leaders Nick Clegg, Menzies Campbell and Paddy Ashdown all made high-profile visits too and the party will feel its efforts have been vindicated as it fights to recover from the near wipeout it suffered at the hands of the Tories in the general election.

For Mr Corbyn, third place is a dismal result and Labour's candidate, Mr Enright, who came second to Mr Cameron in 2015, was among the party activists and former parliamentary candidates who called on Mr Corbyn to quit earlier this year.

Mr Sanders, whose brother Bernie, ran Hillary Clinton close in the race for the Democratic nomination in the US, came to Oxfordshire in the late 1960s and is a former county councillor and social worker.

Fifth place is a humiliation for UKIP after disastrous headlines about its leadership in disarray and MEPs fighting in Strasbourg. Its candidate, Army veteran Dickie Bird, lost his deposit.

The vote coincided with another by-election in Batley and Spen to replace MP Jo Cox who was killed in June.