BBC News Reality Check

The main focus of scrutiny of the PM has been on a May 2020 drinks party in the Downing Street garden.

So, what Covid rules were in place on that date?

The government guidance for England said "workers should try to minimise all meetings and other gatherings” and only "absolutely necessary participants should attend”.

The guidance suggested reducing “the number of people you spend time with in a work setting”.

On top of these guidelines, there were also a number of legal restrictions in place.

People could not leave their homes (or be outside the place they live) without a reasonable excuse, which included work (where you couldn't work from home).

So while anyone attending the party may have broken the law, it might be argued this would not apply to the prime minister himself, because Downing Street is where he lives.

More on this here.

The prime minister apologised for the 20 May Downing Street garden party but said that he believed it was “a work event”.

He added that it “could be said technically to fall within the guidance” but acknowledged that there would be millions of people who would “simply not see it that way”.

So what did the government guidance at the time say?

The guidelines said that in-person work meetings should usually be avoided and if they had to go ahead “only absolutely necessary participants should attend”.

They also stated that meetings should be held: “outdoors or in well-ventilated rooms whenever possible”.

But we could find nothing in the guidelines that makes a reference to socialising or drinking at work.

So it is not easy to see how an event – to which as many as 100 people had been invited to “bring your own booze” – could have fallen within the guidance.

You can read more about what rules were broken here.

The government guidance for England on 20 May 2020 said workplace public gatherings should only take place if they were essential and that "workers should try to minimise all meetings and other gatherings in the workplace". They were also to “reduce the number of people you spend time with in a work setting”.

As well as the issue of the party breaching these guidelines, there were also a number of legal restrictions in place.

People could not leave their homes (or be outside the place they live) without a reasonable excuse, which included work (where you couldn't work from home).

So while anyone attending the party may have broken the law, it might be argued this would not apply to the prime minister himself. That’s because the PM lives in Downing Street and so would not have technically left his home to attend.

The law also prohibited gatherings in a public place of more than two people, unless members of the same household or the gathering was "essential for work purposes". However, lawyers have noted that Downing Street is not a public place.

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During the first lockdown – 27 March to 1 June 2020 – 17,981 fines were issued for breaking Covid-19 restrictions.

We don’t know exactly how many of those were for illegal gatherings of more than 30 people on private properties, but it wasn’t very many. Only 29 fines were issued for that offence in first and second lockdowns put together.

During first lockdown, fines for those attending illegal indoor gatherings of more than 30 people were £100 – or £50 if paid quickly – doubling after each offence.

Not all of the fines imposed will have been paid. Between March 2020 and August 2021, prosecutors checked 2,098 cases that had been challenged. They ruled that 445 had been incorrectly charged and 348 cases were withdrawn.

Away from the Commons, Conservative MP Michael Fabricant has been defending the 20 May 2020 drinks party in the Downing Street garden.

“Some people might have felt that it was actually quite lawful to go from these confined offices into a confined garden,” he told the BBC News channel.

What did the law at the time say?

The law said that “no person may leave the place where they are living without reasonable excuse”, with the reasonable excuses including travelling for the purposes of work.

It also said that no gatherings of more than two people were allowed in public unless “the gathering is essential for work purposes”.

The law did not provide leeway for social gatherings with people you work with.

Indeed, the government guidance at the time was clear that you should “reduce the number of people you spend time with in a work setting” including by “splitting people into smaller, contained teams”.

And it said you could meet one person from another household outdoors as long as you stayed two metres away from them. It's clear that any party, with dozens of people, would have breached these guidelines.

You can read more about the rules at the time here.