Police say they have now issued more than 50 fines for lockdown breaches in Whitehall and Downing Street.
The Metropolitan Police said on Tuesday that they had issued a further 30 fixed-penalty notices, on top of the 20 fines sent out last month, in the Partygate investigation.
Scotland Yard is not providing details of who will be sent a fine, or any further information about the events themselves.
Boris Johnson is not believed to have received a fine yet, with Downing Street claiming that the prime minister will acknowledge if he is sanctioned by police.
In a statement, the Met 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.”
No 10 has been approached about whether the prime minister has been notified about an incoming fine as part of the latest batch of referrals. Johnson is understood to have been present at six of the at least 12 events being investigated.
Liberal Democrat leader Sir Ed Davey said the additional fines “expose the shocking scale of the criminality in Boris Johnson’s No 10”. The former cabinet minister added: “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 said: “This is just the latest example of a distracted out-of-touch government, guilty of breaking the law never mind enforcing it.”
Matt Fowler, co-founder of Covid-19 Bereaved Families for Justice, said the FPN referrals were “indisputable” evidence that there was “rule breaking en masse” in government while families were “unable to be at their loved ones’ sides in their last moments”.
“If Boris Johnson had any decency he would do the right thing and resign immediately,” he said.