BORIS Johnson has been urged to “tell us the truth” about social gatherings and parties at Downing Street after a photo emerged of the PM and staff gathering in the No 10 garden during the first national lockdown.

The Guardian and The Independent previously reported that Mr Johnson was present for 15 minutes at the gathering following a Covid press conference on May 15, 2020.

According to the newspapers’ sources, around 20 staff drank wine and spirits and ate pizza following the press conference at which then health secretary Matt Hancock had told the British public to stay at home “as much as is possible” and stressed the rules in force meant “you can meet one other person from outside your household in an outdoor, public place” as long as you kept two metres apart.

In a photograph published by The Guardian, Mr Johnson can be seen sitting around a garden table with his then-fiancee Carrie, and two members of staff.

On the table are bottles of wine and a cheeseboard.

Four other members of staff are sat around a second table a distance away.

Nine people are then gathered on the grass, with another two sat on the floor to the right.

Downing Street has insisted the gathering was within the rules, and a spokesman previously said: “On May 15 2020 the Prime Minister held a series of meetings throughout the afternoon, including briefly with the then health and care secretary and his team in the garden following a press conference.

“The Prime Minister went to his residence shortly after 7pm.

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“A small number of staff required to be in work remained in the Downing Street garden for part of the afternoon and evening.”

On Sunday, a spokesperson told The Guardian: “As we said last week, work meetings often take place in the Downing Street garden in the summer months. On this occasion there were staff meetings after a No 10 press conference.

“Downing Street is the Prime Minister’s home as well as his workplace. The Prime Minister’s wife lives in No 10 and therefore also legitimately uses the garden.”

But following the emergence of the photographs, Labour’s Ms Rayner tweeted: “I guess staff meetings look a bit different if you went to Eton?

“Enough is enough. Tell us the truth about what was going on in Downing Street from the very beginning immediately @BorisJohnson.”

SNP depute Westminster leader, Kirsten Oswald, said: “This new photo raises more questions and erodes public trust further given Downing St denied this gathering ever took place.

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“A judge-led inquiry is the only way to get to the bottom of all of this after the Cabinet Secretary and the Prime Minister have both been found to have held and attended parties and gatherings at a time when the rest of us were told to abide by coronavirus restrictions.”

She added: “Another civil servant will not do - the Tories will essentially be marking their own homework. We need an independent arbitrator to oversee the inquiry - that owes the UK government nothing - to ensure transparency and that this whole thing is taken seriously.

“Once again we see that the Tories think it’s one rule for them and another for the rest of us.”

Human rights barrister Adam Wagner, who examines coronavirus regulations and interprets them on Twitter for the public, said he had seen the photo and was “doubtful it was against the law”, but that it may have been against guidance.

He said on Twitter that at the time outdoor gatherings were only banned in public places.

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He added that regulations at the time stated “you couldn’t be outside the place you were living without a reasonable excuse” and that working would be such a reason.

And that there was “no way of knowing from a pic that they weren’t working”.

The Prime Minister is alleged to have told one aide that they deserved a drink for “beating back” coronavirus.

Some aides reportedly carried on drinking into the evening, although there was no suggestion Mr Johnson or Mr Hancock had any alcohol or stayed late.

The alleged gathering is one of a number which have been reported across Whitehall during coronavirus restrictions.

Senior civil servant Sue Gray has been tasked with investigating the reports after Cabinet Secretary Simon Case was removed from the probe after it was revealed he had known about a quiz held in his department.