By staff, Agencies UK Prime Minister Boris Johnson has received a formal questionnaire from the Metropolitan Police, and has been required to provide his account of the gatherings at No 10. Sky News reported, citing a PM spokesperson, that Johnson will "respond as required".
According to the reports, the prime minister was contacted via e-mail after 9.30 p.m.
on Friday night.
Similar questionnaires have been sent to more than 50 people who are believed to have attended the "parties" across Whitehall and in Downing Street, with the police investigation dubbed Operation Hillman.
Scotland Yard has specified that receiving such questionnaires does not necessarily amount to being fined over the breach of coronavirus rules, but such a possibility exists if the officers deem it appropriate.
"Clearly, some, but probably not all, of those people may very well end up with a ticket," the outgoing Met Police commissioner Cressida Dick told BBC Radio London this week, when commenting on the ongoing probe into the "partygate" scandal.
UK media reports have already rolled out suggestions about Johnson's possible response to the Metropolitan.
According to The Daily Telegraph, the prime minister will deny breaching coronavirus rules and attending the "Abba" party [one of the six events that Johnson is alleged to have taken part in].
That particular event took place in Downing Street on the night of the departure of former chief adviser Dominic Cummings; there was allegedly a soundtrack featuring songs by the iconic Swedish band.
In order to explain his presence at the gathering, Johnson will reportedly argue to investigators that his No 10 flat can also be a workplace.
In the event of the police not being satisfied with such an explanation, Johnson may face a fine and a possible no-confidence vote from the Conservative Party.
While he believes he will survive it even if he is fined, others argue that it will be "tough" to remain in his position under such circumstances.
The "partygate" scandal has been rumbling around Downing Street for several weeks, with Scotland Yard's investigation of the allegations of government officials partying during tier 2 restrictions continuing right after senior civil servant Sue Gray in her report on the matter accused No 10 of "serious failures of leadership"