Police have now made more than 50 referrals for fixed penalty notices to the ACRO Criminal Records Office over breaches of covid regulations in Whitehall and Downing Street.
The 30 fines are on top of the 20 already issued by cops following the gatherings at the heart of Westminster during lockdown.
It has now emerged that the Prime Minister Boris Johnson and Chancellor Rishi Sunak have been issued fines over the parties.
In a statement, the Metropolitan Police said: "The investigation into allegations of breaches of Covid-19 regulations in Whitehall and Downing Street continues to progress.
"As of Tuesday, 12 April 2022, we have made over 50 referrals for fixed penalty notices (FPN) to the ACRO Criminal Records Office for breaches of Covid-19 regulations who, following the referral, issue the FPNs to the individual.
"We are making every effort to progress this investigation at speed, this includes continuing to assess significant amounts of investigative material from which further referrals may be made to ACRO."
Labour leader Sir Keir Starmer said the announcement of at least 30 more fines relating to the partygate saga has "blown the Prime Minister's defence out of the water".
Speaking during a campaign visit in Glasgow on Tuesday, Sir Keir said: "He claimed to the country that all the rules were being obeyed in Downing Street - where he lives and where he works - that there had been no parties.
"It's now clear there was widespread criminality.
"I think this just not only blows his defence but calls into question his honesty and his integrity."
'Scale of criminality'
Liberal Democrat leader Ed Davey said the fines showed the "scale of criminality" in Number 10.
He added: "These fines expose the shocking scale of the criminality in Boris Johnson's Number 10.
"The police have now completely shredded Johnson's claims that no laws were broken. He cannot be trusted and cannot continue as Prime Minister.
"No other leader in any other organisation would be allowed to continue after law-breaking on this scale.
"If Boris Johnson won't resign, Conservative MPs must show him the door."
Labour deputy leader Angela Rayner has denounced "widespread criminality at the heart of Downing Street".
She said: "Crime is soaring, victims are being let down, and police officers are disappearing from our streets - now we see widespread criminality at the heart of Downing Street.
"This is just the latest example of a distracted out-of-touch Government, guilty of breaking the law, never mind enforcing it.
"Labour has set out a plan to crack down on crime and anti-social behaviour by making offenders pay back to communities and tackling antisocial behaviour with police hubs in every area. Meanwhile, the Conservatives are defending their own law-breaking and are refusing to distance themselves from one of their MP's defence of a convicted sex offender.
"Britain deserves better than this Government."
'Boris Johnson should have resigned a long time ago'
SNP’s Deputy Westminster leader Kirsten Oswald MP said: "These latest partygate fines expose once again Boris Johnson's pathetic defence that no parties were held or that the rules were followed as a lie.
"The sheer scale of rule-breaking at the heart of Downing Street is staggering. People will be looking on in horror as those that set the rules blatantly broke them - making it clear that it's one rule for the Tories and another for everyone else.
“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 rule-breaking parties, but his ego and lack of dignity has led him to desperately cling on.
“The reality is that the longer he stays in office the more lasting the damage will be.”
A former senior official last week became the first person to confirm they had received an FPN as a result of the partygate investigation.
Former deputy cabinet secretary and Whitehall ethics chief Helen MacNamara said she was "sorry for the error of judgment I have shown".
MacNamara, who now works for the Premier League, was reported to have received the fine in connection with a leaving do held in the Cabinet Office on June 18 2020.
Separately, The Guardian has reported that other people had been fined for a gathering held on the eve of the Duke of Edinburgh's funeral last year.
There were also reports that some of the fines issued last month related to coronavirus law-breaking by those who attended a leaving party for a senior official who helped shape the Government's response to the pandemic.
The Daily Telegraph reported that some of those at the farewell event for Kate Josephs, who was director-general of the Cabinet Office's Covid-19 taskforce, have been handed fixed-penalty notices.
The drinks event was held in the Cabinet Office on December 17 2020 at a time when London was under Tier 3 restrictions, banning indoor socialising.
Ms Josephs, who is on discretionary leave from her role as chief executive of Sheffield City Council, has not commented on the report but in January apologised after news of the gathering emerged.
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