Boris Johnson is still to receive the final draft report from the partygate inquiry which could make or break his position as Prime Minister.
Sue Gray has reportedly been stuck in last minute talks over the bombshell report with top officials, Met police and Government lawyers.
The senior civil servant's inquiry is looking into the alleged coronavirus breaches at No 10, including parties during the 2020 lockdown.
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The inquiry chief wants the report to be published in full so needs their sign off before sending it to the Prime Minister, the Mirror reports.
It means Mr Johnson faces an anxious wait as calls continue for him to quit as Prime Minister.
The contents of Ms Gray's report could play a significant role in deciding the fate of Mr Johnson's leadership, with Tory critics waiting for its findings before deciding if they submit formal letters of no confidence in him or not.
Labour leader Sir Keir Starmer suggested Mr Johnson had misled Parliament about Downing Street parties, something which would normally require a minister to resign.
Asked if he would now quit, the Prime Minister said: "No."
Sir Keir said: "We now have the shameful spectacle of a Prime Minister of the United Kingdom being subject to a police investigation, unable to lead the country, incapable of doing the right thing and every day his Cabinet fail to speak out they become more and more complicit."
The PM also faces being interviewed by police after Scotland Yard said Downing Street parties crossed the threshold for investigation.
The Mirror reports that Mr Johnson’s chief of staff, Dan Rosenfield, downplayed the severity of the police probe in a meeting of Government advisors on Tuesday night.
He said: "At worst it will be like getting a fixed penalty fine for speeding, nothing to worry about."
Downing Street has previously said the report will be published in full - and sources close to the Gray inquiry said that was their expectation.
Downing Street said it is the "intention" to publish the report in the format in which Mr Johnson receives it.
The Prime Minister's official spokesman said: "It is simply a reflection of the fact that we have not received the findings and don't know its format, that's why it remains our intention to publish it as received."
The spokesman said he was not aware of the police asking to interview the Prime Minister in relation to the Met inquiry, but "as a rule I'm not going to be getting into individuals who may or may not be involved."
