Boris Johnson’s team thought that the biggest problem they would encounter this week was Sue Gray’s report into allegations of parties at Downing Street in breach of Covid restrictions. However, they now also have a police investigation to deal with. This morning, the Met Police commissioner Cressida Dick confirmed that the police will investigate parties in No. 10.

Giving evidence to the London assembly this morning, Dick said her force had launched a criminal investigation into the allegations triggered by information provided by the Cabinet Office from Sue Gray’s investigation. Dick said: ‘As a result of information provided by cabinet office and my officers own assessment I can confirm (the) Met is investigating.’

So, what happens now? Previously the line from the police had been that it is not their policy was to undertake retrospective investigations of lockdown breaches. However, Gray’s investigation has unearthed evidence that has triggered a change of tack. Dick would not comment on which of the parties her officers are now investigating.

As for the publication of Sue Gray’s report, the expectation is that it will be delayed until the police have carried out their own investigation. in response to the news, the Cabinet Office said ‘the investigation being carried out by Sue Gray is continuing’ — adding that ‘there is in ongoing contact with the Metropolitan Police Service.’

This means potentially weeks and months of uncertainty for the Prime Minister. The fact Boris Johnson’s Downing Street is now the subject of a police investigation is a worrying turn of events indeed for the Prime Minister and his team. Yet opinion is divided on what this means for Johnson’s future. There are Tories who point out that Tony Blair found himself in a similar scenario with he cash for honours investigation in 2007 but rode it out.

That the police investigation has the potential to be lengthy means the whole process could be very drawn out – taking away some of the drama. Plenty of MPs want to wait until the findings of the report until moving. This could allow the Prime Minister to time to try to turn attention back to his domestic agenda. Yet Johnson’s No. 10 being the subject of a police investigation has the potential to be very damaging in itself – and cause MPs to reconsider their support for the Prime Minister.

Update: Despite earlier suggestions that the Cabinet Office would not publish its report until the metropolitan police had concluded their investigations into Downing Street parties, it now appears to be a decision that rests with Sue Gray. The police have indicated that they have no objections to the report being published sooner rather than later.