Senior Downing Street officials joked about holding a Christmas party during lockdown four days after it allegedly took place, leaked footage has revealed.
Downing Street has repeatedly insisted there was no party on Friday, December 18 last year, amid a row as to whether it broke lock down rules.
It has been reported that the alleged event included party games and food and drink being served until past midnight at a time when Tier 3 rules banned work Christmas lunches and parties where it is "a primarily social activity and is not otherwise permitted".
In the footage, Allegra Stratton, then Boris Johnson's press secretary, is seen being questioned about reports of a Downing Street Christmas party. The footage was reportedly filmed as part of preparations for televised briefings by Ms Stratton, which were subsequently abandoned.
At the rehearsal with Ms Stratton on Dec 22, Ed Oldfield, a special adviser to Mr Johnson, asked her: "I've just seen reports on Twitter that there was a Downing Street Christmas party on Friday night. Do you recognise those reports?"
Ms Stratton replied: "I went home," before laughing and then subsequently composing herself.
Mr Oldfield then asked: "Would the Prime Minister condone having a Christmas party?” Ms Stratton responded by asking: "What's the answer?" to which another person in the room can be heard responding: "It wasn't a party, it was cheese and wine.”
Ms Stratton then said: "Is cheese and wine alright?" After laughing again, she went on to say: "This fictional party was a business meeting ... and it was not socially distanced."
On Tuesday night, Sir Keir Starmer, the Labour leader, accused Mr Johnson of lying about the event. He said: "People across the country followed the rules even when that meant being separated from their families, locked down and, tragically for many, unable to say goodbye to their loved ones.
"They had a right to expect that the Government was doing the same. To lie, and to laugh about those lies, is shameful. The Prime Minister now needs to come clean and apologise. It cannot be one rule for the Conservatives and another for everyone else."
Asked on Tuesday whether a party had taken place, Mr Johnson replied: "What I can tell you is that all the guidelines were observed." Questioned about whether he had personally investigated, he said: "I have satisfied myself that the guidelines were followed at all times."
On Tuesday night, government sources outside Downing Street reacted with fury to the video, which they said had tarnished the reputations of ministers who were sent out to play down the controversy in the media.
Senior Tory MPs also called for resignations in Number 10, with one singling out Dan Rosenfield, Mr Johnson’s chief of staff.
Several said ministers and officials across Whitehall had been forced to endure a backlash from industry leaders in their sector over Covid restrictions on the orders of Number 10. Others expressed anger that they had made personal sacrifices last December to comply with the rules while Downing Street staff had seemingly disregarded them.
"We're f-----. How could they be so stupid?" one said.
A former minister said: "It's a disaster, and some extreme humble pie needs to be eaten. I am absolutely furious because we've been trying to make the best of it on the basis of assurances, and this kind of thing just can't happen."
Senior Tory MP Charles Walker said on Tuesday night: "The No 10 party means that any future lockdowns will be advisory, whatever the law says".
The leaked footage was shot in the media room at nine Downing Street, which was refurbished at a cost of ￡2.6 million in preparation for the proposed TV broadcasts.
One source told ITV News, which obtained the footage: "We all know someone who died from Covid, and after seeing this all in the papers I couldn't not say anything. I'm so angry about it all, the way it is being denied."
A Downing Street spokesman said: "There was no Christmas party. Covid rules have been followed at all times."