The Conservatives have held onto former prime minister David Cameron's Witney seat - but saw their majority dramatically slashed.
Robert Courts won the by-election for the Tories, triggered by Cameron's resignation last month, with 45% of the vote.
But the Tories's majority in Conservative-strong Witney was significantly reduced from 25,000 in 2015 to under 6,000 this time round.
The Liberal Democrats made the biggest gains, coming second in the election with 11,611 votes, compared to Courts's 17,313.
David Cameron today joined Prime Minister Theresa May in campaigning for the Conservatives in Witney after his resignation from the seat triggered a by-election.
Former PM Mr Cameron resigned as an MP last month saying he did not want to be a "distraction" for the new Prime Minister.
Today he gave his support to the Conservative candidate for the constituency Robert Courts ahead of the by-election on Thursday.
Mr Cameron, 49, has represented Witney since 2001, becoming Conservative leader in 2005 and PM in 2010.
Labour leader Jeremy Corbyn also visited the constituency to lend his support to Labour candidate Duncan Enright.
Also in the running for the seat is Larry Sanders for the Green Party, businesswoman Liz Leffman for the Lib Dems and Dickie Bird for Ukip.
The Conservative Party has selected a barrister to be its candidate for David Cameron's constituency in Oxfordshire.
Father-of-one Robert Courts, 37, was on Thursday night chosen to run as the Tory candidate for the constituency of Witney & West Oxfordshire.
Speaking after his selection, Mr Courts said he is "hugely honoured" and paid tribute to Mr Cameron.
Mr Courts has been a West Oxfordshire District Councillor since 2014 and was described by the Conservative Party as a "devoted champion for the area".
David Cameron said he is "delighted" at the selection of Mr Courts.
He added: "This was a strong shortlist of local candidates and I'm delighted Robert Courts has been chosen.
"Witney and West Oxfordshire deserves - and will now get - an excellent Conservative candidate to stand up for local people and back Theresa May's government.
"It's been a huge honour to serve Witney and West Oxfordshire and I look forward to helping Robert in the forthcoming by-election."
The former Prime Minister resigned from Parliament earlier this month saying he did not want to be a "distraction" to the government.
David Cameron won't switch on the Christmas lights in his own constituency of Witney this year as he is 'too costly'. Last year's bill - which attracted up to 10,000 people - totalled £45,000, including £2,300 security. Mr Cameron is pictured switching on the lights two years ago.