Rishi Sunak has suffered a double blow after losing both the Kingswood and Wellingborough by-elections.
Labour overturned majorities of 11,220 and 18,540, delivering the Government's ninth and tenth by-election defeats of the current Parliament and securing its second largest swing from the Conservatives ever.
Gen Kitchen secured Wellingborough with 45.8 per cent of the vote, while Damien Egan won Kingswood with 44.9 per cent of the vote.
The results provided Labour with a boost after a U-turn on the party's pledge to spend £28 billion on green projects and an antisemitism row that forced it to drop its candidate for another by-election in Rochdale in two weeks' time.
The twin defeat piles more pressure on the prime minister following the news that the UK entered a recession at the end of 2023.
The results also mean the Government has now suffered the most by-election defeats of any government since the 1960s, surpassing the eight defeats suffered by John Major in the run-up to Tony Blair's 1997 landslide victory.
Labour leader Sir Keir Starmer hailed the victories, saying: "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.”