British Prime Minister Rishi Sunak has suffered a double by-election defeat in safe Conservative seats, with Labour and the Liberal Democrats both overturning majorities of about 20,000.
Labour won Selby and Ainsty and the Liberal Democrats took Somerton and Frome on sizable swings which will leave many Tory MPs looking nervously at their own majorities.
However the Tory leader was spared the prospect of being the first prime minister since 1968 to lose three by-elections on the same day as Labour failed to secure victory in Boris Johnson's former seat of Uxbridge and South Ruislip.
Tory Steve Tuckwell held on with a majority of just 495, down from the 7,210 Mr Johnson secured in 2019.
Speaking this morning, Mr Sunak said the victory in Uxbridge and South Ruislip shows the next general election is not a "done deal".
"Westminster's been acting like the next election is a done deal. The Labour Party has been acting like it's a done deal. The people of Uxbridge just told all of them that it's not," he said.
"No one expected us to win here. But Steve's victory demonstrates that when confronted with the actual reality of the Labour Party, when there's an actual choice on a matter of substance at stake, people vote Conservative."
In Selby and Ainsty, 25-year-old Keir Mather will become the youngest MP in the House of Commons after overturning a 20,137 majority.
For the Liberal Democrats, a 29% point swing in Somerton and Frome saw a 19,213 Tory majority turned into a 11,008-vote cushion for new MP Sarah Dyke.
Liberal Democrat leader Ed Davey said the Somerton and Frome result showed his party was once again winning votes in its former West Country heartland.
"The people of Somerton and Frome have spoken for the rest of the country who are fed up with Rishi Sunak's out-of-touch Conservative government," he said.
The victory means Mr Davey has become the first party leader since Paddy Ashdown in the 1990s to win four by-elections.
For Labour, the failure to secure victory in Uxbridge and South Ruislip in west London has led to a blame game among senior figures over the capital's mayor Sadiq Khan's plan to expand the Ultra Low Emission Zone (ULEZ) to cover outer boroughs.
Labour candidate Danny Beales had distanced himself from the policy, saying it was "not the right time" to expand the £12.50 (€14.45) daily charge for cars which fail to meet emissions standards.
The defeat in the seat was dubbed "Uloss" by a party insider in a sign of the unease at Mr Khan's plan.
In his victory speech, new MP Mr Tuckwell said Mr Khan had cost Labour the seat.
"It was his damaging and costly ULEZ policy that lost them this election," he said.
"This wasn't the campaign Labour expected and Keir Starmer and his mayor Sadiq Khan need to sit up and listen to the Uxbridge and South Ruislip residents," he added.
Labour shadow cabinet minister Steve Reed acknowledged it had been a factor in the campaign.
The shadow justice secretary said: "I think there's been a number of issues at play, but there has certainly been a number of voters who have said to us that they are very concerned about Ulez. Everyone wants to see clean air."
"But for some people, I think, given the chaos that there is in the economy, because the Conservatives have crashed it and the cost-of-living crisis that they fuelled, that this is the wrong time to introduce a charge for ULEZ."
