Labour has gained Wellingborough from the Conservatives, another big by-election victory for Sir Keir Starmer’s party.

Labour’s Gen Kitchen won 13,844 votes, while Tory candidate Helen Harrison polled 7,408, giving her a majority of 6,436.

Ms Kitchen revealed she cut her honeymoon short to campaign, telling Sky News the call to apply for selection came while she was on a Suffolk beach with her husband, dogs, and some fish and chips.

“We packed up the car and we went home. And we went ready to start campaigning for selection,” she said.

Labour wins by-election double header – live updates

Labour managed to achieve a swing of 28.5% – the largest swing of this parliament. The all-time record is held by the Dudley by-election in 1994 – which saw a 29.2% change.

Ms Harrison is the partner of ousted MP Peter Bone, who had represented the Northamptonshire constituency since 2005 and was re-elected with a majority of 18,540 in 2019.

He was removed from his seat last December after an inquiry found he had subjected a staff member to bullying and sexual misconduct, leading to him being suspended from the Commons for six weeks and facing a recall petition which he subsequently lost.

Mr Bone has denied the allegations.

Labour – which won the Kingswood by-election earlier in the night – had enough confidence for a party source to tell Sky News they had secured victory shortly after midnight.

Speaking after the Wellingborough result was announced, Sir Keir said: “These are fantastic results in Kingswood and Wellingborough that show people want change and are ready to put their faith in a changed Labour Party to deliver it.”

Ms Kitchen told Sky News there was “clearly an appetite for change and clearly an appetite for a fresh start”.

In her acceptance speech, Ms Kitchen said: “The people of Wellingborough have spoken for Britain. This is a stunning victory for the Labour Party and must send a message from Northamptonshire to Downing Street.”

Earlier in the night, a Conservative Party source rubbished the idea voters had swapped from the Tories to Labour – instead saying their support stayed at home following the “awful circumstances” of the Wellingborough vote.

Turnout was 38.1% of the eligible electorate – down 26 points from the 2019 general election, with 30,145 votes cast from an electorate of 79,372.

The by-election was seen as a two-horse race between the Tories and Labour, which previously held the seat in 1997 and 2001.

Labour needed a swing of 17.9 percentage points to overturn the Conservatives’ large majority – in other words, the equivalent of a net change of 18 in every 100 people who voted Tory in 2019 switching sides.

The Kingswood and Wellingborough results mean this Conservative government is now the worst performing Tory administration in by-elections since the Second World War.

Like the election in Kingswood, Reform UK – formerly the Brexit Party – gained thousands of votes and had more support than the Liberal Democrats.