The first fines for the parties will be issued on Tuesday, the London Metropolitan Police has confirmed.

The police investigation into so-called partygate will lead to around 20 fixed penalty notices being issued. More are expected to follow the initial flurry.

The police said in a Tuesday morning statement that the investigation into allegations of breeches of COVID-19 regulations in Whitehall and Downing Street has now progressed to the point where the first referrals for fixed penalty notices will be made to ACRO Criminal Records Office.

We will refer 20 fixed penalty notices to be issued for violations of Covid-19 regulations today. The ACRO Criminal Records Office will be responsible for issuing the FPNs to the individual.

The Met Police spokesman stressed that the team was making every effort to progress this investigation at speed and have completed a number of assessments.

He said more work will be done to assess the amount of investigative material that remains, which could result in further fines.

The Met is investigating 12 events, including three that Johnson attended, after issuing more than 100 questionnaires about the possible breeches of COVID-19 regulations.

According to a leaked copy of the generic questionnaire, which was published by ITV News, recipients were informed at the outset that they have an opportunity to provide a written statement under caution.

The police wouldn't say how many people were fined. The prime minister has denied any wrongdoing and is not expected to be among the initial fines.

The leadership challenge that has been driven underground since the start of the invasion of Ukraine could return if the prime minister receives a fine.