As part of their inquiries, the police sent out over 100 questionnaires seeking information about participation in the events.
The Metropolitan Police had launched Operation Hillman following an internal inquiry into what became widely known as the “partygate” scandal.
Last month, the police force had confirmed 20 fines, a number which now goes up to at least 30 more fines or "referrals" for so-called fixed penalty notices to the force's official criminal records unit.
“As of Tuesday, April 12, 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,” the Met Police said in a statement.