Sue Gray is expected to send her report about lockdown busting parties to Downing Street 'in the coming hours' after holding talks with the Met Police.
The Mirror claims the report will be send to Number 10 officials after Ms Gray handed over evidence of possible lockdown breaches to Scotland Yard.
Downing Street will then decide whether or not to publish the report - with the Government suggesting previously this could happen when Parliament sits on Monday.
It is believed the report will comply with the Met Police request to include only “minimal reference” to Downing Street parties the force is investigating.
It is unclear if or when a fuller report with all the details will be published, after the Met finishes its investigation.
The Metropolitan Police asked the top civil servant to make "minimal references" to the parties it is investigating in her report to avoid prejudicing its inquiry.
Scotland Yard is looking at "a number of events" in Downing Street and Whitehall during the pandemic - but the force has not specified which ones.
Reports have suggested it could be as many as eight gatherings.
At the same time, Sue Gray's report had been expected this week but the timing has been thrown into chaos by the Met's bombshell announcement of a police probe on Tuesday.
The Whitehall inquiry is understood to be still ongoing but Ms Gray may be forced to decide whether to delay her report or strip out key details.
Opposition MPs blasted the appearance of an "establishment stitch-up" and a "Whitehall whitewash", which could buy Boris Johnson a reprieve.
The Prime Minister will spend the weekend at his Chequers retreat in Buckinghamshire as he seeks to shore up his battered leadership.
In a statement on Friday, Scotland Yard said: "For the events the Met is investigating, we asked for minimal reference to be made in the Cabinet Office report.
"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."
However some legal figures questioned why publishing the Whitehall report would prejudice the police investigation.
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