Police investigating allegations of lockdown parties held in Downing Street and Whitehall have now made more than 50 referrals for fines.

At least 30 more fixed penalty notices will be issued by the ACRO Criminal Records Office, the Metropolitan Police said in its latest update on Operation Hillman, which is looking into breaches of Covid-19 regulations.

This is up from the 20 referrals for fixed-penalty notices (FPN) the force said had been made at the end of March.

Scotland Yard said it was “making every effort to progress this investigation at speed”, with the possibility of more fines to come.

The identities of people issued with FPNs have not been disclosed publicly by the Met, nor the event a fine relates to.

However, Downing Street has said it will confirm if either Boris Johnson or Cabinet Secretary Simon Case are handed a fine.

No 10 has been approached on whether the Prime Minister or Mr Case have been notified about an incoming fine as part of the latest batch of referrals.

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.”

ACRO Criminal Records Office, the body responsible for issuing the penalties, will now deal with the latest tranche confirmed by police on Tuesday.

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”.

Ms 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.

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.”

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