At least one Number 10 official has received a fixed penalty notice from the Metropolitan Police for attending a lockdown-busting "bring your own booze" event held in the Downing Street garden, Sky News understands.
It is not known who has been fined for the gathering which was held at the height of the UK's first national lockdown on 20 May 2020.
But as of Friday afternoon, it was understood Prime Minister Boris Johnson was not amongst those fined.
Mr Johnson has previously admitted attending the event, but has repeatedly stressed he believed it was a "work event".
The prime minister apologised to MPs in January for being among those at the Downing Street drinks party, saying he spent 25 minutes thanking staff, before returning to his office.
"When I went into that garden just after six o'clock on 20 May 2020, to thank groups of staff before going back into my office 25 minutes later to continue working, I believed implicitly that this was a work event, but with hindsight, I should have sent everyone back inside," Mr Johnson told the Commons.
According to a leaked email, one of the prime minister's then-chief aides, his Principal Private Secretary Martin Reynolds, sent an email to over a hundred employees in Number 10, including the prime minister's advisors, speechwriters and door staff, inviting them to the event.
The email reportedly told staff to "join us at 6pm and bring your own booze".
Mr Johnson said he had not been notified in advance and had "believed implicitly" it had been a work event.
In February, Mr Johnson confirmed that Mr Reynolds would be stepping down from his role as part of a purge of the prime minister's senior team in the wake of the partygate scandal.
Last week the prime minister, Chancellor Rishi Sunak and Mr Johnson's wife Carrie Johnson were all issued fixed-penalty notices for attending an event to mark the prime minister's 56th birthday.
PM to be investigated by parliamentary committee
The prime minister, who has faced persistent calls to resign over partygate and apologised to MPs this week in a performance high on contrition, is thought to have been at more of the 12 events under investigation by Scotland Yard.
On Thursday it was confirmed the prime minister will face a parliamentary investigation into whether he misled MPs when he denied lockdown rules were broken across Downing Street and Whitehall.
MPs backed a Labour-led motion calling for the Privileges Committee to investigate Mr Johnson's conduct.
The motion was nodded through without a vote.
Met Police pauses partygate updates until after May elections
On Thursday, the Met Police confirmed they will not issue any further partygate updates before the May local elections.
Scotland Yard told Sky News the investigation would carry on and officers would continue recommending fines - but the force will not put out media notices on referrals until after 5 May.
But Number 10 had pledged to confirm if the prime minister or cabinet secretary receive any fines before next month's elections.
Until now, it was known that more than 50 fines had been issued in relation to the lockdown-breaking parties in Westminster.
Mr Johnson is currently on his way back to the UK following a two-day official visit to India where he met Indian Prime Minister Narendra Modi.
PM probed on partygate on India trip
On the visit, the PM said he is sure he will still be prime minister in six months despite further rumblings of backbench discontent over partygate.
The PM has faced repeated questions about his future as the scandal continues to dog him despite his attempts to move on to broader issues during his trip to India.
On Friday, Robert Largan became the latest of more than a dozen Tory MPs to speak out against Mr Johnson, telling constituents in a newsletter that he "will not defend the indefensible".