Boris Johnson has said he “briefly attended” Downing Street lockdown gatherings but didn’t know at the time that they “went on far longer than was necessary”.
The prime minister said he had attended to thank staff because it’s “one of essential duties of leadership” and to keep morale as high as possible”.
He told the Commons he had “no knowledge of those subsequent proceedings because I wasn’t there”.
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Mr Johnson added: “My attendance at these moments, brief as it was, has not been found to be outside the rules.
“But clearly this was not the case for some of those gatherings after I had left and other gatherings when I was not even in the building.”
He was speaking after Sue Gray’s long-awaited report said Downing Street leadership must “bear responsibility” for the culture of partying during COVID lockdowns.
The prime minister told MPs he had been as “surprised and disappointed as anyone else in this House as the revelations” came to light, and that he was “appalled” by some of the behaviour in the report.
He said he took “full responsibility for everything that took place under my watch” and also denied he had lied to the Commons when he stated previously that no rules were broken.
The prime minister said he and the government were “humbled” and had “learned a lesson” – and that significant changes had been made to Number 10’s senior staff.
Labour leader Sir Keir Starmer accused Mr Johnson of showing “utter contempt” for the public and that the report demonstrated the “hubris and arrogance” of the government.
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Mr Starmer said it was time for the PM “to pack his bags” and “restore dignity” to the office of the prime minister.
“They [the government] pretend the prime minister has somehow been exonerated, as if the fact he only broke the law once is worthy of praise,” said the Labour leader.
“The truth is they set the bar for his conduct lower than a snake’s belly.”
Sue Gray, a senior civil servant, said the conduct that went on in Number 10 during strict lockdowns fell “well short” of the high standards expected by the public.
Her report looked at 16 events in 2020 and 2021 and found a large number of people had attended events and broken lockdown rules.
Senior staff attended or organised some of them, excessive alcohol consumption was reported, while some staff felt unable to raise concerns.
The report included a number of photos from the gatherings, including one showing the PM with a beer on his birthday, and at a leaving do for an adviser with wine bottles on the table.
At the time, Downing Street staff were among certain workers allowed to continue going into work.
The report’s release had been delayed until police finished their own investigation.
Met Police’s inquiry saw 83 people receive at least one fixed-penalty notice for attending get-togethers over eight dates.