With the vote triggered by Nadine Dorries’ long-burning resignation, it was the largest majority in terms of votes overturned by the party at a by-election since 1945.
Rishi Sunak’s challenge to turn around his party’s prospects looked even harder when Labour’s Alistair Strathern secured a swing of 20.5% to win by 1,192 votes.
In its 105 years of existence, Labour had never won Mid Bedfordshire. They were 24,664 votes behind the Conservatives at the last general election.
But riding a long wave of high national polling and a certain amount of resentment towards Ms Dorries, Labour upended 92 years of Mid Bedfordshire returning Conservative MPs.
Shadow cabinet member Peter Kyle, who ran the campaign in Mid Bedfordshire, said they had delivered a “political earthquake” to Rishi Sunak’s Conservatives after securing a double by-election win.
“This is the biggest by-election shock in history,” he said in an interview with the PA news agency.
“It is a political earthquake and it is one that is sending an unignorable message to Westminster and to Rishi Sunak that this country deserves better.”
In his victory speech, Mr Strathern said a “resounding message” had been sent to the Prime Minister and claimed winning in the seat, a mix of small towns and rural areas, showed “nowhere is off limits” for Labour.
“Tonight residents across Mid Bedfordshire have made history, after decades of being taken for granted, feeling left behind, being underrepresented, they made a decision it was time for a change,” he said.
Mr Strathern, a former maths teacher, made it a double for Labour on a night in which the party also overturned a Tory majority of almost 20,000 in Tamworth.
He fended off the Conservatives’ Festus Akinbusoye, the Bedfordshire Police and Crime Commissioner, who would have been the latest in a straight run of Tory MPs in the constituency going back to 1931 if he had won.
But the former councillor and former Bank of England worker also beat the Lib Dem candidate Emma Holland-Lindsay after a fierce campaign.
The Lib Dems had insisted they were the best placed party to bring over natural Conservatives and win, despite placing third at the last general election, behind Labour.
There had been concerns that the Tories might squeak through on a massively reduced majority because of a split in the anti-Conservative vote. But the Labour victory ended up being by a strong margin, on a 44% turnout.
Ms Dorries, the former culture secretary, had held Mid Bedfordshire since 2005, winning at the 2019 general election with 60% of the vote.
Back in June she announced she would quit with “immediate effect” in protest against not getting a peerage in Boris Johnson’s resignation list, but took nearly three months to make it official.
There was clear anger in the constituency about the “absentee MP”. She had not spoken in the Commons since early July last year, but found time to present her TalkTV show.
Mr Kyle denied it was just down to Ms Dorries that Labour overturned generational Tory voting in Mid Bedfordshire.
“There is no doubt in my mind that had it just been Nadine Dorries and her neglect to this constituency that the Conservatives would have had a reduced majority, but they would have survived,” he told PA.
He said that it was “layer upon layer of poor performance” from the Government, the “lawbreaking” of ministers, a “failure to deliver on key pledges, and also the “language of hatred and division that’s crept into this Government”.
“All of these things have added up to the fact that this community no longer sees its values aligned with those of the Conservative Party that it’s supported for so long,” he said.
The shadow science secretary argued that voters had seen through the Lib Dems after they had come into the constituency “hammering from the left, hammering from the right” and “coming up with statistics that were completely nonsensical”.
“Voters saw through the Lib Dem heat and fury for what it was,” he added.