Boris Johnson and staff pictured with wine in Downing Street garden in May 2020

However, the picture raises questions over that assertion. Bottles of wine are in evidence, there is a lack of social distancing and 19 people are gathered in groups across the Downing Street terrace and lawn.

The prime minister has faced a string of allegations of partying and socialising in No 10 while Covid restrictions were in place. He was forced to order a civil service inquiry, though its head stepped down on Friday over allegations of his own Christmas party.

In the new image shared with the Guardian, Boris Johnson and Carrie, who appears to be holding their newborn baby, are seen sitting around a table with a cheeseboard and wine, along with two people believed to be a civil servant and an aide. Last week No 10 said Johnson was working in the garden before retiring to his flat at 7pm.

On that day Matt Hancock, then health secretary, had given a 5pm press conference urging people to stick to the rules and not take advantage of the good weather over the May weekend to socialise in groups.

There have been a string of accusations that Downing Street staff broke rules by having Christmas parties, with the prime minister presiding over a Zoom quiz and giving a speech at a leaving do.

Johnson ordered an investigation after a video was leaked to ITV showing aides laughing about a Christmas party with wine and cheese, and suggesting passing it off as a business meeting. Simon Case, the cabinet secretary, stepped down from leading that investigation after it emerged his own office had held a Christmas party, and has been replaced by another senior civil servant, Sue Gray.