Keir Starmer asked Boris Johnson “is everything ok?” during prime minister’s questions on Wednesday, as the prime minister dealt with unrest on his own side.
Johnson’s rambling speech to business leaders on Monday in which he lost his place, impersonated a car and spoke about Peppa Pig triggered a fresh wave of criticism from Tory MPs.
A “senior Downing Street source” told the BBC “there is a lot of concern inside the building about the PM” and “it’s just not working.
The anonymous source of the incendiary briefing has been dubbed the “Chatty Pig” in Westminster.
It has been reported some Tory MPs have submitted letters calling for a leadership contest.
Speaking during PMQs on Wednesday, Starmer told Johnson: “Who knows if he’ll make it to the next election.
“But if he does, how does he expect anyone to take him and his promises seriously?
“His chancellor is worried people are getting wise. His backbenchers say it’s embarrassing. Senior people in Downing Street tell the BBC it’s just not working.”
Starmer, repeating a question asked to Johnson by a TV interviewer earlier this week, added: “Is everything ok prime minister?”
SNP Westminster leader Ian Blackford also asked if Johnson has considered quitting “before he’s pushed out the door”.
Johnson hit back: “I tell you what’s not working, it’s that line of attack. We are delivering for the working people of this country.”
He added: “I think what the people of this country want to hear is less talk about politics, they want to talk about what the government is doing.”