Conservative activists filmed dancing at a Christmas party during Covid restrictions in 2020 were invited to “jingle and mingle”, according to an invitation seen by the BBC.
Thirty people were invited to the 14 December event at Conservative party headquarters.
At the time London was under Tier-2 restrictions which banned indoor socialising.
Police are reviewing video of the event first published by the Mirror.
In the footage, one person is heard saying it is OK to film “as long as we don’t stream that we’re, like, bending the rules”.
The Conservative Party said four people were disciplined over the event, although it has not named them.
The event was held on behalf of Shaun Bailey’s unsuccessful Mayor of London campaign, and Mr Bailey has previously apologised for attending the event, which was thrown for party activists.
He was awarded a peerage in Mr Johnson’s resignation honours list last week.
Ben Mallet, a former aide to the ex-prime minister who was awarded an OBE last week, is shown chatting to guests in the latest footage.
Housing Secretary Michael Gove apologised for the video, and told the BBC the footage was “terrible” and would leave people feeling “extremely angry”.
Media caption, Watch: What the new Partygate video shows
In November 2022, Scotland Yard said it was taking no action against Mr Bailey or other people who attended the gathering.
On Monday, the force said is was now “assessing video footage that was not previously provided to officers” in the party.
In a 45-second video published by the Mirror newspaper, people can be seen drinking and standing in groups, while a man and a woman can be seen holding hands and dancing.
One member of the party can be heard asking: “Are you filming this?”
A man then laughs before saying: “As long as we are not streaming that we’re bending the rules.”