Boris Johnson has apologised for the Downing Street partygate saga, saying: “I get it and I will fix it”.
The Prime Minister was hauled to the Commons following the publication of Sue Gray's report, which revealed 12 events were being probed by police - including one in his own No11 flat.
He faced shouts of "resign" from opposition MPs as Labour leader Keir Starmer branded him "a man without shame".
In extraordinary scenes, SNP Westminster leader Ian Blackford was kicked out of the chamber for failing to withdraw his claim that the PM had lied to the House.
Ex-PM Theresa May accused Mr Johnson of failing to understand his own rules - and Tory big beast Andrew Mitchell said he no longer supported him.
Ms Gray published a slimmed down report on Monday after days of legal wrangling, following Scotland Yard's decision to investigate.
The top civil servant tore into "failures of leadership and judgment" in No 10 and the Cabinet Office while people in England lived under strict Covid curbs over the past two years.
In a 12-page report, she said there was "too little thought" given to what was happening in the country at the time and added: "Some of the events should not have been allowed to take place."
Ms Gray revealed that police were investigating 12 parties, including a party in the PM's flat and a birthday gathering where he was surprised by cake.
Mr Johnson told the Commons: "Firstly, I want to say sorry - and I'm sorry for the things we simply didn't get right and also sorry for the way this matter has been handled.
"It's no use saying this or that was within the rules and it's no use saying people were working hard. This pandemic was hard for everyone."
He vowed to overhaul the Downing Street operation and to strengthen the code of conduct for advisers.
But furious Keir Starmer said: “The Prime Minister himself is now subject to criminal investigation”.
The Labour leader tore into the PM, and branded him unfit for office.
But he went on: “It is already clear the report discloses the most damning conclusion possible.
“Over the last two years the British public have been asked to make the most heart-wrenching sacrifices.
"A collective trauma, endured by all, enjoyed by none. Funerals have been missed. Dying relatives unvisited.
"Every family has been marked by what we’ve seen through and revelations about the Prime Minister’s behaviour have forced us all to re-think and re-live those darkest moments.”
He said the British people had stood up and been tested but their sacrifice "will forever be tainted by the behaviour" of the PM.
He added: "By routinely breaking the rules he set, the Prime Minister took us all for fools.
"He held people’s sacrifice in contempt. He showed himself unfit for office."
Mr Starmer accused the PM of hiding behind the police investigation and said "the British public aren’t fools".
"They think the Prime Minister should do the decent thing and resign," he said. "Of course, he won’t. Because he is a man without shame."
The SNP's Ian Blackford got into a furious row with Speaker Lindsay Hoyle for refusing to withdraw his claim the PM had misled MPs.
Amid furious shouting, Mr Blackford walked out the chamber.
Ex-PM Theresa May said No10 "was not observing the regulations they had imposed on members of the public.”
In a scathing attack, she said: “Either [the Prime Minister] had not read the rules, or didn’t understand what they meant - and others around him - or they didn’t think the rules applied to them. Which was it?”
Senior Tory backbencher Andrew Mitchell became the eighth MP to say the PM shout quit.
He said: "When he kindly invited me to see him 10 days ago, I told him that I thought he should think very carefully about what was now in the best interests of our country and of the Conservative Party, and I have to tell him he no longer enjoys my support."
