Police are investigating a so-called 'Abba party' which allegedly took place in Boris Johnson's Downing Street flat.
The Prime Minister previously denied any parties took place in Downing Street on November 13 2020.
However, a report published today by senior civil servant Sue Gray shows that both she and Scotland Yard looked into 'a gathering' in Mr Johnson's No 10 flat.
The alleged bash took place just over a week after Mr Johnson ordered a lockdown in England, closing pubs and restaurants and banning indoor household mixing.
Ms Gray is understood to have been told about allegations claiming Carrie Johnson held a party the night Cummings resigned on November 13, 2020.
The Mirror reported last year that No 10 aides “drank their socks off” and new reports, also denied by Mrs Johnson’s spokeswoman, suggest they played Abba’s The Winner Takes It All to celebrate her adversary quitting.
However, when the PM was previously asked in Parliament if there was “a party in Downing Street on November 13”, he replied: “No”.
Ms Gray's report revealed Scotland Yard are probing 12 out of the 16 parties she investigated - including Boris Johnson's birthday party.
Separate claims have emerged that Ms Gray was informed that some of Mrs Johnson’s friends had the access code to their private flat.
And it has been alleged that a tipsy Downing Street staffer boasted about breaching lockdown rules to police guarding No 10, telling them, “we’re the only ones allowed to party”, as they left in the early hours.
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Ms Gray's found "failures of leadership and judgement" over lockdown parties that "should not have been allowed".
Her damning nine-page "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."
But the report was stripped of key details after the Met Police asked Ms Gray to make only "minimal reference" to 12 of the gatherings in her report.
Ms Gray conceded: "I am extremely limited in what I can say about those events. It is not possible at present to provide a meaningful report setting out and analysing the extensive factual information I have been able to gather."
Labour called for the PM to finally “end the circus” over partygate.
Shadow minister Lisa Nandy said: “There are a lot of bereaved families, there are a lot of people who made huge sacrifices who deserve to hear the truth from the Prime Minister.
"If he won’t put an end to this circus then that report has to come out in full so that people can judge for themselves.”
