Video report by ITV News Deputy Political Editor Anushka Asthana
The prime minister will receive a copy of Sue Gray's report into alleged Covid-19 lockdown breaking parties "shortly" and will not wait for the police inquiry to conclude, ITV News understands.
It is anticipated Boris Johnson will be handed the report in the near future, it will then be redacted in line with the police request and will then likely be published next week.
It was thought the full report would have been published far sooner, but earlier this week the Metropolitan Police asked Ms Gray to make “minimal reference” to the Downing Street events it is investigating.
It was confirmed on Friday that the Met had received material from the Cabinet Office to support its investigation, while stating the police have not delayed the publication of Ms Gray's report.
The Met had repeatedly resisted pressure to formerly investigate allegations of rule-breaking on Downing Street, despite evidence piling up, before Commissioner Cressida Dick announced on Tuesday that a criminal inquiry had been launched.
That decision is understood to have been taken after Ms Gray - the civil servant investigating partygate - passed on to the force evidence she'd uncovered of potentially criminal wrongdoing.
One former Metropolitan Police chief superintendent has said he's "confused" as to why the force wants Ms Gray to omit details from her partygate report.
Dal Babu gave a scathing assessment of how the force has handled the case, saying he would have expected a criminal inquiry to have been launched much sooner than it was.
Mr Babu said he is "struggling to understand why this report would impede the police investigation", given it has "no legal standing" and there is already a huge amount of evidence in the public domain.
The force had initially said it did not investigate Covid breaches retrospectively and insisted there was insufficient evidence to investigate until this week.
Mr Babu, however, said he "would have expected the police to have intervened at a much earlier stage", given the "significant evidence of criminality".
In a statement, the force said: “For the events the Met is investigating, we asked for minimal reference to be made in the Cabinet Office report.
Anushka Asthana analyses the delay in publication
“The Met did not ask for any limitations on other events in the report, or for the report to be delayed, but we have had ongoing contact with the Cabinet Office, including on the content of the report, to avoid any prejudice to our investigation.”
The Met demanded "minimal references" are made to the eight events in question so those being investigated cannot see statements from others in advance, ITV News Deputy Political Editor Anushka Asthana said.
Ken Macdonald, the former director of public prosecutions (DPP), said the move seems "disproportionate" in the face of "very powerful" public interest in the report's swift publication, unless there is "more serious conduct" being investigated.
Mr Babu, explaining how the Met will conduct its inquiry, said: "The police will come in and caution witnesses, they'll interview them, and they'll issue, I should imagine, Fixed Penalty Notices. It's relatively straightforward.
"So I'm a little bit confused as to why this report is maybe an obstacle to the police moving forward."
The request appears to explain why the inquiry still hasn't been released, despite Boris Johnson's premiership resting upon it.
The intervention makes it "hard to see" how Ms Gray could publish "anything meaningful" before the police have concluded their inquiries, ITV News Political Editor Robert Peston said.
A spokesperson for Sadiq Khan - who, as Mayor of London, is the equivalent of a Police and Crime Commissioner for London - said: “Sadiq has always been clear that the Met must police without fear or favour.
"Anything less than a full investigation with transparency about the process will damage public trust.”
Scotland's first minister, Nicola Sturgeon, said the situation is getting "murkier by the minute", adding how it appears the process of inquiry is "aiding Johnson at the expense of public accountability".
She went on: "I doubt Johnson cares about damage to the reputations of others - individuals or institutions - as long as he saves his own skin. But these things matter. Rapid conclusion and full publication of the findings of inquiries surely now essential for public trust."
Labour leader Sir Keir Starmer said Mr Johnson was unfit for office and the scandal about rule-breaking in Downing Street was distracting him from tackling the cost of living crisis.
"What I want to see is Sue Gray's report in full and the investigation finished as quickly as possible.
"Because we're in this situation where the whole of government is paralysed because the police are looking at what the Prime Minister was getting up to in Downing Street.
"On the one hand, you've got people really worried about their bills and you've got these investigations going on into what the prime minister was up to.
"He has paralysed the government so the sooner we get both the full report and the investigation completed, the better."
What does this all mean for Boris Johnson?
For the prime minister - who was initially expected to receive and release the report on Wednesday - any delay provides more time for him to try and gain support from Tory MPs who had been considering whether to oust him.
Backbench Tories unhappy with the PM's handling of partygate had said they would reserve judgement on whether he should be removed as prime minister until after Ms Gray's report is published.
In the meantime the PM has been holding face to face meetings with scores of Tory MPs in a bid to persuade them he is the best person to lead their party.
However it is difficult to see how he could cling on to power if Ms Gray's report, and/or the police investigation, finds he knowingly broke the rules and therefore misled Parliament with his explanation that he did not.
More letters of no confidence in the PM's leadership are sure to be submitted if he is found to have lied to Parliament, joining the around 20 which have already been submitted - it takes 54 to trigger a vote of no confidence which could remove Mr Johnson as Tory leader.
Partygate - what is alleged?
At least eight government parties are being looked into by Ms Gray and the police are investigating a "number" of those events.
Ms Gray is a highly respected civil servant, the second permanent secretary at the Department for Levelling Up, who was asked to probe the party reports after the previously appointed investigator, Simon Case, was implicated in one of the allegations.
Several allegations of coronavirus rule breaking have been levelled at the prime minister, with the most recent being a birthday bash in June 2020, revealed by ITV News.
But the accusation with perhaps the most potential to damage the PM is he attended a rule-breaking party in the Number 10 garden in May 2020, after his principal private secretary sent an email inviting more than 100 staff to bring their own booze and "make the most of the lovely weather".
The prime minister accepted he did attend that event, which was clearly in breach of rules at the time, but he claimed to be oblivious of the party, believing it was a "work event".
It's that claim - made to Parliament - that is putting his leadership at risk, because if it's found to be untrue, the ministerial code dictates he must resign.
Ms Gray's report, which the PM still hasn't seen, will be make for "very uncomfortable reading", Peston has been told.