Downing Street staff are said to have partied until 1am at boozy leaving drinks held the night before Prince Philip's funeral.
Fresh details have emerged of the two gatherings held in No 10 on April 16 2021, hours before the Queen sat alone to mourn her husband of 73 years at a service at St George's Chapel in Windsor.
The night before, officials danced while drinking wine in plastic cups, ordered takeaway pizza and tried out Boris Johnson's son Wilf's slide, according to The Telegraph.
Government guidance at the time warned: “You must not socialise indoors except with your household or support bubble.
“You can meet outdoors, including in gardens, in groups of six people or two households.
Boris Johnson has apologised to the Queen for the events, which he said he "deeply and bitterly" regretted.
The Prime Minister was not at either event as he was at his Chequers country retreat, No 10 said when the events were first reported last week.
The latest details come as the PM was battling to save his premiership, with plans to spend the weekend at Chequers trying to win over his mutinous MPs.
Officials allegedly took part in a seven-hour drinking session at two separate dos to say farewell to Boris Johnson's top spin doctor and a Downing Street photographer.
The Telegraph claims to have obtained a picture of staff in the Downing Street basement, where people were drinking wine and spirits out of plastic cups.
Text messages also indicate that attendees were still partying at 1am, having started at around 6pm.
The existence of photos and texts could provide further fuel for Sue Gray's partygate inquiry, which is expected to be published next week.
One of the events was for James Slack, the PM's departing director of communications, which was held in the press area and then the garden.
He has apologised for the bash. He said in a statement: “This event should not have happened at the time that it did. I am deeply sorry, and take full responsibility.”
The second event for a photographer, which was held in the basement, where an adviser alleged acted as a DJ using a laptop.
Wine was reportedly spilled on a printer where the laptop was blaring music out.
The events reportedly merged when they eventually moved to the garden, where it is alleged that some attendees went down a child's slide belonging to the PM's son Wilf.
It was previously claimed that Wilf's swing had been broken by guests.
Mr Johnson appeared visibly distressed when he told reporters that he had apologised to the Queen over the parties.
"I deeply and bitterly regret that that happened," he told reporters this week.
"I can only renew my apologies both to Her Majesty and to the country for misjudgments that were made, and for which I take full responsibility.''
The revelations about the parties last week sparked a major backlash, compounding the Prime Minister's woes as he battles for his own survival.
The claim that an aide was dispatched to the Co-op supermarket on The Strand to fill a suitcase with wine was widely mocked.
Last week, the Prime Minister's official spokesman said: “It is deeply regrettable that this took place at a time of national mourning.
"No 10 has apologised to the Palace."
