Boris Johnson: People invited to Downing Street drinks in May 2020 when lockdown rules were in place

It is claimed that as many as 100 people were invited to a drinks event in the Downing Street garden during the first lockdown.

The BBC has been told the Prime Minister and his wife were among about 30 people who attended the gathering on 20 May 2020.

Boris Johnson wouldn't say if he was there or not, as he says an investigation is underway.

An email - revealed by ITV news - was sent out inviting people to "socially distanced drinks in the No 10 garden this evening".

It was sent when lockdown rules were still in place which wouldn't have allowed a party like this - and the BBC understands that several Downing Street members of staff spoke of their concerns about the event.

Which other gatherings are being investigated?

This isn't the first time claims have been made about parties at Downing Street during times of tight coronavirus restrictions.

This latest issue follows reports about other gatherings including a photo showing the Prime Minister, his wife and government staff sitting together in the garden of No. 10 with wine and cheese.

Mr Johnson has said this was not a party and those present were "people at work, talking about work".

There is also an investigation taking place into a number of alleged parties at Downing Street in November and December 2020 when there were also restrictions in place.

Also - the man who was asked by the Prime Minister to investigate if parties were taking place - Simon Case - had to stand down when it emerged a quiz was being held by his office on 17 December.

Senior civil servant Sue Gray is now leading the investigation into these gatherings.

What restrictions were in place on 20 May?

In England, you could only meet one other person from another household outdoors, with advice to remain 2m (6ft) apart.

Larger gatherings with people from other households were not allowed, apart from a few exceptions, such as funerals, or where the gathering was essential for work purposes

Schools, non-essential shops, hospitality venues and hairdressers remained closed.

Why does it matter?

There were restrictions in place in May 2020 because of Covid-19

At the time this party is said to have taken place, there had been an increase of coronavirus cases and the government was asking people to be sure to follow the lockdown rules.

That same night the then-Culture Secretary, Oliver Dowden, gave the Downing Street coronavirus briefing, saying: "You can meet one person outside of your household in an outdoor, public place provided that you stay two metres apart."

As with all of the parties being investigated, there is a lot of anger that the government was asking people to follow the rules while, behind closed doors, people who work for them seemingly weren't.

Thousands of of people were issued with fines for breaking rules on gatherings in 2020, according to figures from the National Police Chiefs' Council.

ITV News has published what appears to be an email invitation sent on behalf of Mr Johnson's principal private secretary, Martin Reynolds.

"After what has been an incredibly busy period we thought it would be nice to make the most of the lovely weather and have some socially distanced drinks in the No 10 garden this evening," part of the the email says.

What have people said?

BBC sources have said that several Downing Street members of staff expressed concerns about drinks happening at the time.

A message sent by one Downing Street staffer to another at the time, shown to the BBC, said: "Um. Why is Martin (Reynolds) encouraging a mass gathering in the garden?" Another asked: "Is this for real?"

On Monday Downing Street declined to comment on the story and the Prime Minister - when asked if he attended - said that this gathering, like others reported to have happened under coronavirus restrictions during 2020, is now being looked into as part of an ongoing independent investigation.

Health Minister Edward Argar told BBC Breakfast he understood the "anger, sadness and upset many will feel about these allegations". But he said it was "important" to allow an investigation to take place into gatherings in Downing Street before coming to any conclusions.

Labour MP Ed Miliband says the Prime Minister could be in a "very difficult position"

The opposition Labour Party said the prime minister would face "serious questions" if he was found to have attended.

Senior Labour MP Ed Miliband told BBC Breakfast Mr Johnson would find himself in a "very difficult position" if he was found to have "broken the rules and potentially broken the law".

A Metropolitan police spokesperson said the Greater London police service was "aware of widespread reporting relating to alleged breaches of the Health Protection Regulations at Downing Street on 20 May 2020 and is in contact with the Cabinet Office", which oversees government policy.