Police will not announce any new fines in its partygate investigation until after the local elections in May, Scotland Yard has said.
The prime minister has already paid one fixed-penalty notice (FPN) for attending his own birthday party in the Cabinet Room of No.10 on June 2020.
Police have been looking into 12 events in total, including multiple gatherings attended by Johnson.
Scotland Yard has so far issued 50 FPNs in the course of its partygate inquiry.
On May 5 people across the country will go to the polls in the local elections.
A Met spokesperson said on Thursday: “Whilst the investigation will continue during the pre-election period, due to the restrictions around communicating before the May local elections, we will not provide further updates until after May 5.”
In the run-up to elections, a period known as purdah, the government is expected not to make big announcements that could give it an electoral advantage.
But it is not usually seen to apply to police inquiries. It means while fines may still be issued, the Met will not make any announcements.
Previously the Met made public that fines had been issued, although it did not name who had been given them.
The announcement that Johnson and Rishi Sunak had been given FPNs came from No.10 not the police.
It is understood that No.10 would reveal if the prime minister was fined again before the elections.
It comes as MPs look set to approve Labour’s plan for the Commons privilege committee to launch a new inquiry into whether Johnson lied to parliament when he denied rules had been broken in No.10.