Sue Gray is expected to deliver her report on No 10 parties to the PM without waiting for the police inquiry to conclude, the BBC has been told.
The senior civil servant is expected to hand her report to the prime minister shortly but no exact timescale has been given.
It comes after days of confusion over when the report would be published.
The Met Police has denied its investigation is to blame for any delay.
The police had asked for minimal references to be made to the events they are looking at, in order to “avoid any prejudice to our investigation”.
This means the report Ms Gray releases before the police probe is complete may need to contain some redactions, or be changed.
Downing Street is yet to receive the document, which it has promised to publish.
Material from the Cabinet Office, which the Met requested to “support its investigation into potential breaches of Covid-19 regulations at a number of events in Downing Street and Whitehall”, was received by the force on Friday.
In a statement, the Met said it expected to approach individuals “identified as having potentially breached” regulations.
Commander Catherine Roper, who leads the Met’s Central Specialist Crime Command, said “the offences under investigation, where proven, would normally result in the issuing of a fixed penalty notice”.
She added that the Met’s actions would be “proportionate to the nature of these offences”.
BBC political correspondent Iain Watson said he had been told Ms Gray was trying to redraft parts of her report to address any police concerns – but wanted to avoid blanking out whole swathes of text in case it looked like “a Whitehall whitewash”.
Former director of public prosecutions, Lord Macdonald, told the BBC that asking for Ms Gray’s report to make only minimal reference to the gatherings being investigated by police seemed “disproportionate” if the force was only considering fixed penalty notices.
Labour has called for the report to be published in full and the investigations to be wrapped up as soon as possible.
The SNP and Liberal Democrats are claiming the delay in publication is a “stitch-up” aimed at keeping Boris Johnson in power.
If anything less than that full report emerges next week, we can expect even more condemnation from the opposition parties.
All this is crucial to the prime minister’s political future because some Conservative MPs have been telling me that they’re considering putting in a letter of no confidence once they’ve read Sue Gray’s report.
If that report is shorn of all the serious allegations of what was going on in Downing Street, it may well be the case that they sit on their hands until the Met completes its work.
The opposition say this is obviously to the advantage of Boris Johnson – it buys him some time.
But there’s a bigger issue too, because it’s not just the opposition politicians.
Some Conservatives are saying to me too that the way all this has been handled has further eroded public trust in the political system.
Many Conservative MPs are saying they will wait for the report’s publication before deciding whether to take action against the prime minister.
Mr Johnson has been under pressure following a string of allegations about events held in Downing Street and other government premises during coronavirus restrictions.
It has already been confirmed that the events Ms Gray is looking into include a “bring-your-own-booze” drinks event in the No 10 garden in May 2020, which was attended by Mr Johnson, and a staff gathering to celebrate his birthday in June 2020.
On Tuesday, Met Police Commissioner Cressida Dick announced that the force was investigating.
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The SNP’s Westminster leader, Ian Blackford, said: “If the UK government refuses to publish the full unredacted report it will prove, yet again, that Westminster is utterly corrupt and broken beyond repair.
“It won’t save Boris Johnson’s skin. It will only add to the calls for him to go.”
Liberal Democrat leader Sir Ed Davey said: “Anything short of the full report would be a Whitehall whitewash not worth the paper it is written on.”
And Labour leader Sir Keir Starmer said: “What I want to see is Sue Gray’s report in full and the investigation finished as quickly as possible.”
Sir Roger Gale, who is among the Tory MPs to have publicly called for the PM to resign, said the situation was a “farce” which could delay a possible challenge to the “lame duck” prime minister.
Speaking on BBC Radio 4’s The World At One, he added that unless there is a “legal barrier”, the senior official should publish her report “now and in full”.
Asked by the BBC’s Nick Robinson if the police’s statement had been helpful to Mr Johnson, senior minister Jacob Rees-Mogg said: “It would be a very eccentric conspiracy theorist who thought that the prime minister being investigated by the police is beneficial for the prime minister – that is parallel universe stuff.”
Timeline: The alleged government gatherings
The government is facing mounting pressure over several events that are alleged to have been held during lockdowns. Here is what we know about them and the restrictions in place at the time:
Boris Johnson announced a plan to take the “first careful steps” out of the lockdown that began in March 2020. But he said people should continue to “obey the rules on social distancing and to enforce those rules we will increase the fines for the small minority who break them”.
Legal restrictions at the time said you could not leave your house without a reasonable excuse and government guidance was that you could meet one person outside of your household in an outdoor setting while exercising.
A photo from May 2020 showed the prime minister and his staff with bottles of wine and a cheeseboard in the Downing Street garden. When asked about it, Boris Johnson said, “those people were at work talking about work”.
About 100 people were invited by email to “socially distanced drinks in the No 10 garden” on behalf of the prime minister’s principal private secretary, Martin Reynolds.
Witnesses told the BBC the PM and his wife were among about 30 people who attended.
Boris Johnson has confirmed he attended the event, saying he was there for 25 minutes and “believed implicitly that this was a work event”.
On Boris Johnson’s birthday, up to 30 people gathered in the Cabinet Room at No 10 to present the prime minister with a birthday cake and sing Happy Birthday, according to a report by ITV News.
No 10 said staff had “gathered briefly” to “wish the prime minister a happy birthday”, adding that he had been there “for less than 10 minutes”.
Rules at the time banned most indoor gatherings involving more than two people.
Boris Johnson announced plans for a “significant return to normality” in England by Christmas “through targeted, local action” instead of national lockdowns.
But he added that the timetable relied on “every one of us staying alert and acting responsibly”.
With cases of coronavirus rising again, the prime minister told people in England that “we are once again asking you to stay at home” as a new national lockdown began.
He said people should only leave their homes “for work if you can’t work from home, for education, and for essential activities and emergencies”. Indoor gatherings with other households were banned, unless they were for work purposes.
Sources told the BBC that Downing Street staff members attended a gathering with Carrie Johnson in the flat where she and the prime minister live. A spokesman for Mrs Johnson denies the party took place.
A leaving event was held for No 10 aide, Cleo Watson, where people were drinking, and Mr Johnson made a speech, according to sources.
The second national lockdown ended after four weeks but Boris Johnson replaced those restrictions with “tough tiers to keep this virus down”.
London was placed in tier two, which banned two or more people from different households from meeting indoors, unless “reasonably necessary” for work purposes.
The Department for Education has confirmed it had an office gathering to thank staff for their work during the pandemic. It says drinks and snacks were brought by those who attended and no outside guests or support staff were invited.
The Conservative Party has admitted that an “unauthorised gathering” took place at its HQ in Westminster. It was held by the team of the party’s London-mayoral candidate, Shaun Bailey, who has since stepped down as chair of the London Assembly police and crime committee. The Metropolitan Police is to speak to two people who attended the party.
Multiple sources have told the BBC there was a Christmas quiz for No 10 staff last year. A photo – published by the Sunday Mirror – showed Boris Johnson taking part and sitting between two colleagues in No 10. Mr Johnson has denied any wrongdoing.
London moved into the highest tier of restrictions and Matt Hancock, who was health secretary at the time, said it was important “everyone is cautious” ahead of the festive period.
The Department for Transport apologised after confirming reports of a party in its offices that day, calling it “inappropriate” and an “error of judgment” by staff.
A leaving party was held at the Cabinet Office for the outgoing head of the civil service Covid taskforce – the team responsible for drawing up coronavirus restrictions.
Kate Josephs, now chief executive of Sheffield City Council, apologised for the event, saying she was “truly sorry that I did this and for the anger that people will feel as a result”.
Downing Street originally denied a report by the Daily Mirror that a party took place in Downing Street.
However, a video obtained by ITV News showed the prime minister’s then-press secretary Allegra Stratton, joking about reports of an event, saying: “This fictional party was a business meeting and it was not socially distanced.”
Lockdown restrictions were eased in England, with pubs and restaurants allowed to reopen with outdoor service only.
However, working from home continued to be recommended and socialising indoors with people from other households was not allowed. Meeting others outdoors was limited to groups of six people or two households.
Two parties were held by Downing Street staff at No 10, the night before Prince Philip’s funeral.
One of the events was a leaving party for the PM’s then director of communications James Slack, who has apologised for the event and acknowledged it “should not have happened at the time that it did”.
Boris Johnson was not at either party.