Boris Johnson has claimed that "nobody told me" that a boozy lockdown bash in the Downing Street garden broke Covid rules.
The under-fire Prime Minister broke cover for the first time in days to insist that he hadn't lied to Parliament about the event in May 2020, which he has admitted attending for 25 minutes.
He pulled out of a visit last Thursday after a family member tested positive for coronavirus - and he has not been seen in public since.
Mr Johnson looked pale and drawn on a visit to a hospital in north London today as he battles to save his premiership amid widespread anger from the public and his own MPs.
He is facing renewed calls to quit after continuing allegations of rule-breaking parties in Downing Street - and accusations he has lied to Parliament.
The PM admitted to MPs last week that he briefly attended a BYOB gathering in the No 10 garden on May 20 2020 - but tried to claim he thought it was a work event.
Former No 10 aide Dominic Cummings mounted another attack on his former boss on Monday night, claiming the Prime Minister had "lied to Parliament" and multiple witnesses "would swear under oath" that he was told about the event.
In an explosive blogpost, Mr Cummings said the PM was warned that the event was against the rules but he "waved it aside".
Asked if he had lied to the public and Parliament, Mr Johnson told broadcasters: "No. I want to begin by repeating my apologies to everybody for the misjudgments that I've made, that we may have made in No 10 and beyond, whether in Downing Street or throughout the pandemic.
"I do know how infuriating it must be for people up and down the country, in view of the huge sacrifices people have made... to think that didn't happen in 10 Downing Street.
"On that point, nobody told me that what we were doing was against the rules, that the event in question was something that wasn't a work event, and as I said in the House of Commons when I went out into that garden, I thought that I was attending a work event."
He repeatedly rejected Mr Cummings' claim that he had been warned about the event in advance and he was now lying about it.
Pressed again that he was lying, Mr Johnson said: "Nobody told me, nobody said that this was something that was against the rules, that was a breach of the COVID rules or you're doing something that wasn't a work event because frankly I can't imagine why on earth we would have gone ahead."
He added: "I do humbly apologise to people for misjudgments that were made but that is the very, very best of my recollection about this event, that's what I've said to the inquiry.
"I carry full responsibility for what took place but nobody told me, I'm absolutely categorical, nobody said to me this is an event that is against the rules."
The PM claimed he only saw the now infamous "bring your own booze" invite sent to staff by his principal private secretary Martin Reynolds "the other day... when it emerged".
In a lengthy interview, Mr Johnson appeared distressed when he was grilled over the latest revelations that there were two boozy leaving dos at Downing Street on the eve of Prince Phillip's funeral last year.
The Queen was pictured sitting alone at the service the next day, in line with the Covid regulations at the time.
Mr Johnson could be heard breathing heavily behind his mask as he told reporters: "I deeply and bitterly regret that that happened.
"I can only renew my apologies both to Her Majesty and to the country for misjudgments that were made, and for which I take full responsibility.''
The PM pleaded for people to wait for the results of Sue Gray's official inquiry into allegations of rule-breaking parties in Downing Street and across Whitehall.
The senior civil servant is probing a string of allegations of parties, including several bashes revealed by the Mirror.
Mr Johnson declined to say if he would resign if he was found to have misled Parliament.
Labour Deputy Leader Angela Rayner said: “Boris Johnson clearly knows it’s the end of the road.
“He’s the Prime Minister, he set the rules, he didn’t need anyone to tell him that the party he attended broke them.
“If he had any respect for the British public, he would do the decent thing and resign.”
