Both victors in Thursday's remarkable by-elections, which took place at opposite ends of the country, used their speeches to attack Boris Johnson and call for his resignation.
Simon Lightwood, the Labour winner in Wakefield, West Yorkshire, told his cheering supporters that Mr Johnson’s "contempt for this county is no longer tolerated."
Nearly 300 miles away in Crediton, Devon, the Liberal Democrat winner Richard Foord told the assembled crowd: "Every day Boris Johnson clings to office, he brings further shame, chaos and neglect."
The excoriating remarks were made at elections in which neither Conservative candidate stayed to speak to the media to give their thoughts on the reasons for the defeat.
In Wakefield, Mr Lightwood began his speech: "Tonight, the people of Wakefield have spoken on behalf of the British people. They have said unreservedly: 'Boris Johnson, your contempt for this country is no longer tolerated'.”
'Rebuilding the Red Wall'
He went on to tell the assembled crowd that Labour was now "rebuilding the red wall".
Mr Lightwood added: "We're rebuilding the trust of the electorate and people are ready for a fresh start.
"They're sick of all the lies and deceit of Boris Johnson and we offer that alternative vision.
"People in Wakefield and across the country are sick of the deceit and dishonesty of this Government."
Only a few minutes later, former army major Mr Foord warned Tory MP’s that if they continued to support Mr Johnson, they would face further losses.
He said: "Tonight, the people of Tiverton & Honiton have spoken for Britain. They’ve sent a loud and clear message: It’s time for Boris Johnson to go. And go now.
"Every day Boris Johnson clings to office, he brings further shame, chaos and neglect. Communities like ours are on their knees.
"I also have a simple message for those Conservative MPs propping up this failing Prime Minister: The Liberal Democrats are coming.
"If you don’t take action to restore decency, respect and British values to Downing Street, you too will face election defeats like the one we have seen here tonight.
"It is time to do what’s right for our country. You know in your heart that your leader is not the person to lead this great nation into the future.
No sitting Prime Minister has lost two by-elections in a single day since John Major in 1991.
Earlier this week Mr Johnson described suggestions he should quit if the Tories lost both by-elections as "crazy".
'Coups can happen'
Mr Foord also warned Boris Johnson that "coups can happen" when leaders head overseas during rocky patches at home.
The Prime Minister is currently in Rwanda, and is expected to be out of the country for several days.
Speaking just after his win on Friday morning, Mr Foord was asked if the Prime Minister had been "missing in action" from the campaign trail.
"The Prime Minister is obviously free to go and speak to counterparts on the world stage but actually he should be mindful of the fact that often when presidents and leaders are overseas, that's when a coup can happen," Mr Foord said.
Nadeem Ahmed, the Conservative candidate for Wakefield, was not seen at the election until moments before the winner of the election was announced.
As the results were read out and the Labour supporters began cheering, Mr Ahmed used the distraction to slip out of the packed hall and into the morning twilight.
Ironically, one Tory staffer was overheard during the evening claiming Mr Ahmed was so amiable, chatty and well liked in the constituency he couldn't walk down the street without saying hello to someone.
Andrea Jenkyns, the Tory MP for Morley and Outwood told the Telegraph: “I hope we keep one. It would be nice to keep one at least.”
She later told reporters: "On the doorstep in certain areas we went there really is a great love for Boris. I really did find that in the working class areas."