Boris Johnson will cooperate with a police inquiry into alleged Downing Street parties as clouds of suspicion hang over No 10.
Metropolitan Police chief Dame Cressida Dick made a bombshell announcement that the force would probe "a number of events" in No 10 and Whitehall during the pandemic after being handed information by top civil servant Sue Gray.
Ms Gray's report into 'partygate' has now been thrown into doubt by the news of a police investigation, with conflicting reports on when it would be published.
It comes as a major blow to the Prime Minister who is battling for his political life as mutinous MPs openly plot his downfall.
He told MPs it is "right" for Scotland Yard to investigate and that he believes it will "help to draw a line under matters".
But the 'partygate' row may have already inflicted too much damage to Mr Johnson premiership.
The Mirror's Head of Politics Jason Beattie takes a look at what the latest developments mean for Boris Johnson.
If the way Boris Johnson governs is wearying so is the protracted nature of his demise.
Whatever appetite there was for Government as a branch of soap opera it has been sated by the antics of this Prime Minister.
Such is his histrionic nature that he cannot depart the stage with quiet dignity.
This misery may end today with the publication of Sue Gray’s report.
Since the storm of partygate first broke the Prime Minister has used every trick in the book to avoid being held to account.
When his initial defence - there were no parties - crumbled under the weight of evidence that there was not just one knees-up in Downing Street but an apparently endless number of jollies, get-togethers and sing-a-longs he resorted to the last refuge of a minister in trouble: an Cabinet Office inquiry.
For as long as Sue Gray was investigating he could hide behind the excuse that he could not comment until the report was published.
It also caused Tory MPs plotting his downfall to sheath their knives until Gray delivered her judgement.
This was a desperate ploy by a desperate Prime Minister.
His survival rested on the hope that Gray’s findings would echo her name by being sufficiently grey for him to argue his behaviour was an error rather than a crime.
But what he really needed was time.
In the past Johnson has wheedled his way of trouble by making a cod apology, waiting for the outcry to calm down and then hoping everyone will forget about it.
This is how he hopes to wriggle off the hook of partygate.
That, with time, the country will move on from suitcases of wine, late-night karaokes and birthday cakes and allow Johnson the chance to reboot his tattered and tatty premiership.
Some in Downing Street had hoped the investigation by the Met Police may offer that reprieve.
Then it emerged the publication of Gray’s report is imminent.
Even if Johnson survives Gray’s verdict, which already look ominous given she has unearthed enough material to be of interest to the police, there is no escape from the purgatory of partygate.
He will be living under the cloud of the Met inquiry for weeks, possibly months.
In the eyes of most of the public he will be regarded as guilty until proven innocent.
An already dysfunctional Downing Street will struggle to operate while it remains under suspicion of criminal activity.
The paralysis disbars Johnson from relaunching his beleaguered premiership and trying to rebuild his reputation with a disillusioned electorate.
The stench of double-standards will haunt the Conservatives into this May’s local elections and beyond.
Loyal backbenchers yesterday called for a ’sense of proportion’ and suggested the partying was a trivial distraction at a time when the country is struggling with the cost of living and Russia is edging towards war in Ukraine.
More realistic Tory MPs realise how dire this is for Johnson.
To claim partygate is an irrelevance is to wilfully ignore the ignominy of the Prime Minister being at the centre of a police investigation.
Any Conservative trying to excuse Johnson cannot have heard Cressida Dick explain that one of the thresholds for the deciding to launch the probe was a potentially “serious and flagrant” breach of the law.
The question Tories are now asking themselves is whether Johnson can limp on or has he so irretrievably damaged their party’s reputation they should get rid of him now.
Like the ringmaster of a diabolical circus he ushers in one scandal after another, whether it is refurbishment of the No 10 flat, accusations of blackmail by his whips or reportedly sacking a minister for her “Muslimness.”
Will Gray’s report be enough to convince Tory MPs it is time end this carnival of chaos?