BORIS Johnson has been proven a liar and should resign, his opponents have said after the Metropolitan Police confirmed at least 20 instances of Covid rules breaches in Downing Street and Whitehall.

Labour and the SNP called for the Prime Minister to quit and accused of him breaking the ministerial code as officers announced 20 fines will be issued in the first tranche of sanctions.

The imminent issuing of the fixed penalty notices (FPNs) means the police have ruled the law was broken – with more fines expected to follow as officers continue to sift through evidence.

But No 10 has denied the Prime Minister misled the House of Commons when he defended the goings-on in his home and workplace.

Johnson is not thought to be among those set to receive a fine at this stage – despite it being understood he was present at six of the at least 12 events being probed – as he is contesting the allegations and took advice from his personal lawyer on how to respond.

Keir Starmer had last month backtracked on calls for the PM to quit, but Labour's deputy leader Angela Rayner said on Tuesday "Boris Johnson's Downing Street has been found guilty of breaking the law" and that the Tory leader must resign.

The SNP’s deputy Westminster leader, Kirsten Oswald, cited comments from the Prime Minister in which he denied there was any rule breaking on Downing Street.

On December 8, after the initial partygate reports were published in the press, he told MPs: "I have been repeatedly assured that the rules were not broken. I repeat that I have been repeatedly assured since these allegations emerged that there was no party and that no Covid rules were broken."

Oswald said: “The confirmation by the Metropolitan Police that the law was broken and initial fines have been issued expose Boris Johnson’s remarks that no parties were held or that the rules were followed as being flatly untrue.

“This damning development once again highlights the scale of rule-breaking at the heart of Boris Johnson’s corrupt government.”

The National: Kirsten Oswald MP

She continued: “While the public were following the rules imposed upon us all and making difficult sacrifices to protect each other, Boris Johnson and his Tory colleagues were breaking them without a care.

“The public will rightly want answers and accountability, and it is vital that there is transparency in this ongoing investigation and that must involve full disclosure of precisely who, among ministers and senior civil servants, is being fined for breaking the law.

“Boris Johnson should have resigned a long time ago over the boozy rule-breaking parties, but his ego and lack of dignity led him to desperately cling on.

“The reality is that the longer he stays in office the more lasting the damage will be.”

READ MORE: How many parties did the Tory government hold in lockdown? The full list (so far)

The Prime Minister's official spokesman said Downing Street had not been informed by the Met that Johnson is among those referred to the ACRO Criminal Records Office, which is responsible for issuing the penalties.

“We’ve said we’ll update if that were to occur but our position has not changed,” he said.

He refused to be drawn on whether Johnson would resign if he did get a fine.

He also declined to say whether fined individuals can carry on working in No 10, though former chief whip Mark Harper suggested law-breaking civil servants or special advisers would have to be sacked. In a tweet, the Tory MP posted a screenshot of the Civil Service Code, highlighting a passage saying they must “comply with the law”.

The identities of those fined will not be disclosed by Scotland Yard.

Downing Street said it will confirm if Johnson is issued with a FPN, but not if others in his family or office are.

No 10 staff will not need to come forward if they get a FPN, but they will be asked to update their vetting information depending on their security clearance.

The PM’s spokesman said Johnson had not been misleading on the numerous occasions he defended the saga, despite wrongdoing now being confirmed.

“At all times, he has set out his understanding of events,” he said.

“The Prime Minister has apologised to the House already.”

He added: “You can expect to hear more from the Prime Minister when the investigation is concluded and Sue Gray has set out her report.”

Labour deputy chief Rayner commented: "The culture is set from the top. The buck stops with the Prime Minister, who spent months lying to the British public, which is why he's got to go.

"This has been a slap in the face of the millions of people who made huge sacrifices."

LibDem leader Sir Ed Davey added: “If Boris Johnson thinks he can get away with partygate by paying expensive lawyers and throwing junior staff to the wolves, he is wrong.

“We all know who is responsible. The Prime Minister must resign, or Conservative MPs must sack him.”

The Met would not say how many individuals will get a fine – it is possible some will get more than one if they attended more than one event.

The force would also not say which parties the fines relate to.

Johnson came under intense pressure to quit as a result of partygate, but in recent weeks the war in Ukraine has seen Tory MPs rally round their leader.

But the Met’s intervention, confirming it believes laws were broken at the heart of Government, could reignite the debate about his leadership.

Hannah Brady, spokeswoman for Covid-19 Bereaved Families for Justice, said the PM’s team had “regularly and blatantly” broken “the same rules that families across the country stuck with even when they suffered terribly as a consequence”.

The group on Tuesday marked a year since they began to draw hearts on the national Covid memorial wall in London, and Brady – whose father Shaun died at 55 after contracting Covid – said: “It’s crystal clear now that whilst the British public rose to the challenge of making enormous sacrifices to protect their loved ones and their communities, those at 10 Downing Street failed.

“Frankly, bereaved families have seen enough. The PM should have resigned months ago over this. By dragging it out longer all he is doing is pouring more salt on the wounds of those who have already suffered so much.”