A defiant Prime Minister stood before MPs at Prime Minister's Questions less than 24 hours after his Commons apology for breaching lockdown restrictions at a Downing Street gathering in 2020.
And he delivered a withering assessment of his opposite number Sir Keir, who served up more of the same as he continued his campaign to oust the man who destroyed Labour at the last general election.
Pressed again over why he had not resigned for "breaking the rules", Mr Johnson said of Sir Keir: "I fear he's in some kind of Doctor Who time warp.
"We had this conversation yesterday and I've explained why I bitterly regret receiving a fixed penalty notice and I've apologised to the House.
"We're going to get on with delivering for the British people, making sure that we power out of the problems that Covid has left us – with more people in work that there were before the pandemic, fixing our energy problems and leading the world in standing up to the aggression of Vladimir Putin."
The PM slammed the "intellectual bankruptcy" of Labour, saying: "They have no plans for energy, they have no plans for social care and they have no plans for the economy."
Sir Keir focused his attacks on leaked claims from a meeting the PM held with Tory MPs on Tuesday night, where according to the Labour leader, Mr Johnson criticised the BBC and the Archbishop of Canterbury.
He accused Mr Johnson of opting to "slander decent people" in private but lacking the "backbone to repeat it in public".
His call for the PM to apologise to the archbishop, one of the PM's biggest critics, was rejected, while Mr Johnson said comments attributed to him regarding BBC's coverage of Ukraine had "absolutely no basis or foundation in truth".
Sir Keir - who was reprimanded by the Speaker on Tuesday for calling the PM "dishonest" - was asked by Tory MP Sir David Evennett to withdraw his inaccurate comments about the BBC.
The continuation of the row came as MPs prepared to debate and vote on a Labour motion calling for Mr Johnson to be investigated over claims he misled parliament.
Conservative MPs across the West Midlands are expected to support the Prime Minister, who will miss the session as he will be on a state visit to India.
Meanwhile Michael Fabricant MP has responded to comments Sir Keir made about one of his Lichfield constituents, John Robinson, who the Labour leader said had been unable to hold his wife's hand while she was dying of Covid as he was following restrictions.
Mr Fabricant said he was "sad to hear" about Mr Robinson and accused Sir Keir of weaponising tragedies people went through during the pandemic.
Mr Fabricant told GB News: "The saddest thing of all I think is the way that Keir Starmer and other politicians have chosen to weaponise the personal tragedies endured by people like John Robinson and I would have thought actually that was pretty beneath them."
He added: “It's such an emotional issue and the word 'Partygate' has become part of our vocabulary.
"When I think of a party, I think of people blowing party poppers, drinking and rolling around, you know, with friends and all the rest of it.
"And it was nothing like that, but people aren't interested in that.
"I suspect as things drift on, you know, we'll move on to other issues.”