Labour’s total of 11,176 votes in the by-election was smaller than the Conservative majority of 11,220 at the last general election, while the number of Tory votes was down by 19,037.
The turnout was 37.11%.
The final result was:
Damien Egan (Labour) 11,176
Sam Bromiley (Conservative) 8,675
Rupert Lowe (Reform UK) 2,578
Lorraine Francis (Green) 1,450
Andrew Brown (Liberal Democrats) 861
Nicholas Wood (UKIP) 129
Labour received 44.9% of the vote while the Conservative share fell fto 34.9%, representing a swing to Labour of 16.4%.
The decision of Chris Skidmore, who had held Kingswood for the Conservatives for nearly 14 years, to force a by-election placed the area in the national political spotlight and heaped more pressure on Prime Minister Rishi Sunak.
Mr Skidmore, a former energy minister and champion of the UK’s commitment to net zero carbon emissions, quit over the government’s Offshore Petroleum Licensing Bill, which would “cause future harm” through the promotion of new oil and gas production.
The Conservatives chose their group leader on South Gloucestershire Council, Sam Bromiley, to defend the seat.
Cllr Bromiley left Thornbury Leisure Centre without giving interviews after the result was declared in the early hours of February 16.
He later issued a statement on social media, which said: “Thank you to all those who voted Conservative in the Kingswood by-election. I have thoroughly enjoyed the last few weeks meeting residents and hearing about their concerns and ideas for our area.”
Mr Sunak said the result “shows that we’ve got work to do to show people that we are delivering on their priorities”.
Reform UK, the successor to the Brexit Party, came third in an election the party had originally said it would not contest because of the cost to the taxpayer.
Candidate Rupert Lowe, received 2,578 votes – the first time the party had a share of 10% or more at a Westminster by-election. He said afterwards that those who voted for him had “sent Westminster a message”.
A spokesperson for South Gloucestershire Council said it had applied for £189,000 from the government to cover the total cost of running the by-election.