Boris Johnson has been branded "unfit for office" after top civil servant Sue Gray said several Downing Street lockdown parties "should not have been allowed".
Her nine-page interim update said "at least some" of the gatherings were "a serious failure to observe not just the high standards expected of those working at the heart of Government, but also of the standards expected of the entire British population at the time."
Here are the main questions - and answers - you may have after today.
How damaging was the Sue Gray report for Boris Johnson?
That Boris Johnson is now fighting for his political life is now beyond doubt.
Senior civil servant Sue Gray pulled no punches, concluding "there were failures of leadership and judgment" in No10 and "excessive consumption of alcohol" that was "not appropriate in a professional workplace".
The sheer number of rule-breaking parties cops are now investigating -12 in total - across the 20-month period also underlined the scale of rule-breaking which was taking place behind closed doors.
Ms Gray warned "excessive consumption of alcohol is not appropriate in a professional workplace", that Downing Street "felt unable" to blow the whistle and how key workers across the country were following the rules while "working under equally, if not more, demanding conditions" that Downing Street staff.
Labour leader Keir Starmer described the Prime Minister in the Commons as "a man without shame".
How has Boris Johnson responded to the report?
The Prime Minister issued another grovelling apology and told MPs “I get it and I will fix it”.
"It's no use saying this or that was within the rules and it's no use saying people were working hard," he said. "This pandemic was hard for everyone."
He announced a shake-up of the No10 operation, with a new 'Office for the Prime Minister' to be created with its own private secretary. The government will also review the civil service and special adviser codes of conduct - but not ministers'.
The PM will also be clinging to the hope that the public will move on to other issues, such as the Ukraine crisis and the government's hastily-pulled-together White Paper for levelling up.
How did Tories react?
The level of anger on the Conservative Party benches was clear to see.
Former Prime Minister Theresa May led criticism, saying the report made clear rules were not obeyed in Downing Street, saying: "So either my right honourable friend 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 Number 10. Which was it?"
Meanwhile, former minister Andrew Mitchell told the PM he could no longer support him and Aaron Bell, an MP from the 2019 intake, said he had attended his grandmother's funeral during the first lockdown but could not hug his parents.
"Does the prime minister think I'm a fool?," he asked.
Is Boris Johnson now safe?
It remains up to Conservative MPs as to whether Boris Johnson continues as Prime Minister.
Under Tory Party rules, 15% of MPs (54) must send a letter saying they have no confidence in the PM to trigger a vote. Mr Johnson needs 50% to win (180).
It is not clear whether Tories are angry enough to move against their embattled leader. Despite rivals Rishi Sunak, Liz Truss and Tom Tugendhat making clear they fancy a tilt at the top job, there is no frontrunner yet.
Some MPs may also be biding their time and hoping the PM can absorb responsibility for the May local elections, which if polls are correct,
will be devastating for the party.
