ITV has reported that sources who attended the alleged party in Downing Street, which would have breached Covid rules at the time, reported an alarm being triggered, which resulted in police attending.
Staff in Downing Street allegedly gathered on December 18 last year for a Christmas celebration including cheese and wine, causing controversy.
The Met Police has so far not investigated the allegations, saying that there was not enough evidence.
However, sources are now telling ITV that the Met Police actually attended the party to check a security breach as an alarm was triggered.
According to the ITV report, a government spokesperson said: "Given there is an ongoing review, it would be inappropriate to comment while that is ongoing. We do not discuss matters of security.”
The Met Police added: "As a matter of course, we do not discuss specific details of protective security arrangements we provide at government buildings, as to do so could serve to undermine any such arrangements in place."