No 10 Lockdown Christmas Parties are just one big laugh and it’s at our expense.

The prime minister has been repeatedly quizzed about what was reported to have been a large party on Friday 18 December last year.

According to newspaper reports, around “40 or 50” people are alleged to have crammed “cheek by jowl” in a room in Number 10.

Just two days earlier, on 16 December, London had been put into Tier 3 of coronavirus restrictions, which prevented mixing indoors with people not in your household.

Any party at Downing Street would have breached the government’s guidelines at the time.

Its guidance for the Christmas period specifically said: “Although there are exemptions for work purposes, you must not have a work Christmas lunch or party, where that is a primarily social activity and is not otherwise permitted by the rules in your tier.”

The other question is whether it would have been illegal.

London at the time was in Tier 3 and the law banned gatherings of two or more people indoors unless it was “reasonably necessary” for work.

There was also a specific prohibition on organising an indoor gathering of more than 30 people.

But there may have theoretically been a loophole for government buildings like 10 Downing Street because of the 1984 legislation used to bring in the tier system, according to Adam Wagner – a barrister at Doughty Street Chambers and an expert on Covid regulations.

Another barrister, Charles Holland from Trinity Chambers, tweeted that there would have needed to be an agreement with Westminster City Council for the regulations to apply in Downing Street.

The Metropolitan Police has said it does not “routinely investigate retrospective breaches” of Covid laws, after two Labour MPs called for a formal investigation into the party last week.

Writing separately to Met Police Commissioner Dame Cressida Dick on Friday, Labour MPs Neil Coyle and Barry Gardiner called for a full investigation into whether or not any laws had been broken.

Sharing his letter on Twitter, Mr Coyle, the MP for Bermondsey and Southwark, in south London, said from reading the guidance, he believed “holding these events was a breach of the rules at the time”.

He said: “Like most constituents, I followed the rules and did not see my own dad last Christmas and, sadly, it was to be his last.

“The sense of outrage from constituents is palpable that they followed the rules whilst those responsible for devising and enforcing them were breaching them at the top of government.”

His comments were criticised by Conservative MP Lucy Allan, who said: “Is this what you were sent to Parliament to do? Is this what you want the police to spend time doing?”

Also sharing his correspondence on Twitter, Mr Gardiner, the MP for Brent North, in north-west London, said: “I hope you agree that no-one is above the law and your service needs to maintain public confidence that Covid rules apply equally to all people.”

He added he was “surprised” to hear Dame Cressida tell LBC the force was not currently investigating the party.

In a statement, the UK’s largest police force said it was “aware of widespread reporting” of “alleged breaches of the Health Protection Regulations” at a government building on two dates in November and December.

The Met added it was the force’s “policy not to routinely investigate retrospective breaches” of Covid laws but said it would “consider” the letters it had received.

Starmer says ‘NO’ to criminal investigation

However, any calls for a criminal investigation have been severely knocked with the Labour leader Sir Keir Starmer claiming a criminal investigation was not needed saying:

“We don’t need a criminal investigation, we need a prime minister who is honest about it.

“I think what should happen now is the prime minister should be honest.

“They know that party took place, they know what happened – have the guts to be honest about it,” he added.

It seems both Starmer and the Tories think it’s one rule for them and one for the others.