The report’s conclusions contradict much of what Boris Johnson has previously said, as UK Editor Paul Brand reports
Boris Johnson has once again faced calls to resign from within his own party after an inquiry into alleged rule-breaking in Number 10 and Whitehall found there had been "failures of leadership and judgment" under his watch.
Sue Gray's partygate report condemned a "serious failure" in Downing Street to observe coronavirus standards and said "a number" of gatherings should not have been allowed to take place.
The civil servant added that the Downing Street garden was "used for gatherings without clear authorisation or oversight" and "this was not appropriate".
Mr Johnson accepted her findings and apologised, saying he is "sorry for the things we simply didn't get right and also sorry for the way that this matter has been handled".
He said he would "learn from these events and act now" by implementing changes to improve the running of government.
But that was not enough to satisfy former Cabinet minister Andrew Mitchell, who told MPs that the PM no longer has his support, moments after Mr Johnson's predecessor Theresa May stuck the knife in.
Ms May said: "The Covid regulations imposed significant restrictions on the freedoms of members of the public.
"They had a right to expect their prime minister to have read the rules, to understand the meaning of the rules and indeed those around him to have done so too and to set an example in following those rules.
"What the Gray report does show is that Number 10 Downing Street was not observing the regulations they had imposed on members of the public, 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?"
Labour leader Sir Keir Starmer said Mr Johnson should resign, but he is "a man without shame. And just as he's done throughout his life he's damaged everything and everyone around him".
Ms Gray said a number of the parties she investigated represent "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".
Critics have rounded on the prime minister from all sides, reports Deputy Political Editor Anushka Asthana
Tory MP Aaron Bell spoke of attending his grandmother's funeral where only ten people were allowed to attend around the same time that rules were allegedly being broken on Downing Street.
"Does the prime minister think I'm a fool? he asked, as he recounted a funeral at which he wasn't allowed to hug his parents or siblings.
The SNP's Westminster leader Ian Blackford said Mr Johnson had "wilfully misled Parliament" with his previous claims that all rules were followed in Downing Street at all times during the pandemic.
He said the report was a "farce" with "no facts", adding: "The prime minister has told the House that all guidance was completely followed, there was no party, Covid rules were followed and that 'I believed it was a work event'.
"Nobody, nobody believed it then. And nobody, nobody believes you now, prime minister. That is the crux - no ifs, no buts - he has wilfully misled Parliament."
He left the Commons after being asked to do so over his refusal to withdraw his claim that Mr Johnson lied to MPs.
Michael Heseltine, a prominent MP under Margaret Thatcher's and John Major's Tory government, said Mr Johnson is undoubtedly in "very serious trouble".
He also added that the PM should publish Ms Gray's report in full and immediately.
"If it's going to drag on, that's going to have a debilitating debate on government, on Britain's reputation on the world."
Former Tory party heavyweight Michael Heseltine says the PM has made a 'big mistake'
Meanwhile, Conservative MP Angela Richardson said she resigned as Michael Gove's parliamentary secretary as she shared her "deep disappointment" at the parties scandal.
In a statement on Facebook, she said: “Sue Gray’s report published today clearly states that there were failings at Number Ten Downing Street that let us all down.
“I share the deep disappointment that it has taken so long to get to this stage when there could have been an early acknowledgement and apology."
UK Editor Paul Brand explains why the report doesn't draw a line under the scandal
Which parties are being investigated by the Metropolitan Police?
Of the 16 parties Ms Gray looked into, just four are not subject to criminal investigations which have been launched by the Metropolitan Police.
Among those being investigated is a gathering in the Cabinet Room in No 10 on Boris Johnson's birthday in 2020, which was first revealed to have taken place by ITV News.
Labour leader Sir Keir said that means "there can be no doubt" the prime minister himself is the subject of a criminal investigation.
Here are the 12 events being investigated by police:
20 May - Number 10 BYOB garden party
18 June - A Cabinet Office leaving party
19 June - The PM's birthday gathering, where he was presented with cake
13 Nov - A party in the PM's Downing Street flat and a leaving party for a special adviser
17 Dec - Two Cabinet Office parties, one Number 10 leaving party
18 Dec - 10 Downing Street Christmas party
14 January 21 - Leaving party for two private secretaries
16 April 21 - Two Number 10 leaving parties
The Met says it was passed a "bundle of evidence" by Ms Gray's team, which includes 300 pieces of paper, "about a ream and a half", and 300 photographs.
What did the partygate report find?
Ms Gray said the conclusion of her report was that: "A number of these gatherings should not have been allowed to take place or to develop in the way that they did.
"There is significant learning to be drawn from these events which must be addressed immediately across government. This does not need to wait for the police investigations to be concluded."
Ms Gray also criticised the culture in Downing Street as she attacked the "excessive consumption of alcohol" in Downing Street, which she said is "not appropriate in a professional workplace at any time".
"Steps must be taken to ensure that every government department has a clear and robust policy in place covering the consumption of alcohol in the workplace."
She pointed out that some staff wanted to raise concerns about behaviour they witnessed in Downing Street but "felt unable to do so".
Responding to Ms Gray's findings, Mr Johnson said: “I get it, and I will fix it. I want to say to the people of this country I know what the issue is.”
Labour MPs shouted back: “You!”
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When will we see Sue Gray's full report?
Ms Gray accepted that the document she passed to the PM cannot be described as a "meaningful report" because she has made "minimal reference" to the gatherings on the police are investigating.
She said she hasn't set out "the extensive factual information" she has.
The civil servant did however say she would keep all the evidence she has uncovered in "secure storage" for "safekeeping" until it "may be required".
The PM would not commit to releasing the full, unedited report when the police inquiry concludes, despite previously promising that Ms Gray's findings would be published in full.
"At that stage I will take a decision," he said.
But Number 10 said Mr Johnson will "ask Sue Gray to update her work in light of what is found" by police and "he will publish that update".
The document is a watered-down version of the full report, which was finished last week but edited to remove aspects referring to potential criminality, which the Metropolitan Police is investigating.
It means details likely to be the most damaging to the PM have been omitted from the report and there are serious concerns that they may never be revealed.
The PM has publicly said he is "deeply sorry for misjudgements" surrounding events in No 10, but insisted no one warned him a garden party in the first lockdown would be against the rules.
Many Tory MPs have said they are reserving judgement on whether to remove the PM from office over his involvement in partygate until Ms Gray's report was published.
But the PM's day of reckoning may have to wait, with any details referring to potential criminality withheld from the report until at the earliest, when the police investigation concludes.
Watch in full as Boris Johnson responded to the partygate report