Downing Street has suggested it may be up to Boris Johnson to decide what is published in the inquiry report into rule-breaking Downing Street parties.
It comes as the Prime Minister's former top-aide Dominic Cummings claimed witnesses are "very worried" about handing evidence to the investigation.
Mr Cummings, who was formerly Boris Johnson's righthand man, also said he is only corresponding with Sue Gray, the civil servant investigation allegations of lockdown-breaking Downing Street parties, in writing.
He said it means the PM cannot "invent things I've supposedly said" and he will not be given "more chances to lie".
Mr Cummings wrote in his blog: “I know others are very worried about handing things to the Cabinet Office because they know the PM will see everything SG collects.
“This inevitably means that evidence, including photos, is not given to her and instead will keep leaking after her report. (To stress, this is a consequence of beliefs about the PM’s integrity, not SG’s.)
“Other damaging stories will come out until he is gone.”
He suggested “many officials are desperate” to force Mr Johnson out this week.
On why he will not be meeting Ms Gray and will instead submit evidence in writing, he wrote in his blog: "When SG (Sue Gray) asked to speak to me I emailed to the effect: if we speak the PM will invent nonsense and spin it to the media and you and I will both have problems, let’s keep everything in writing, therefore he cannot invent things I’ve supposedly said to you, there is only a written record, this makes both our lives easier.
“She agreed. So I have answered questions in writing and will answer further questions in writing if she wants.
“But I will not speak and therefore provide the PM with more chances to lie and confuse everybody.”
Watch Boris Johnson's apology as he admits attending the May 20, 2020, party at the Downing Street garden.
Ms Gray is the top civil servant who is investigating a series allegations about parties and social gatherings that broke Covid rules.
These include a “bring your own booze” event in the Downing Street garden on May 20, 2020, which the Prime Minister has admitted attending, saying he thought was a work event.
Ms Gray is also investigating two leaving bashes held in Downing Street the night before the Duke of Edinburgh’s funeral last year.
The PM's official spokesman said: "It’s very much our intention to publish the findings in full as set out in the terms of reference”.
Asked if it was up to the Prime Minister or Ms Gray what could be published, the spokesman said: “I think it is a report that comes to the Prime Minister.”
It has been reported that Ms Gray had spoken to Metropolitan Police officers stationed at Downing Street, and that the prime minister's wife Carrie could be interviewed.
Ms Gray's report is expected to be released later this week. Mr Johnson previously said the report would be published in the House of Commons library.
Tory peer's dramatic resignation
Many Conservative MPs waiting for the report to be published before deciding whether to submit letters of no confidence.
Tory peer Lord Agnew of Oulton, a Cabinet Office and Treasury minister, on Monday in the House of Lords dramatically quit the government over the “schoolboy” handling of fraudulent Covid business loans.
He outlined his unhappiness with working between the Department for Business, Energy and Industrial Strategy (BEIS) and the Treasury: “Schoolboy errors were made, for example, allowing over 1,000 companies to receive bounce back loans that were not even trading when Covid struck.”
Lord Agnew denied the partygate scandals linked to the prime minister were the reason he resigned.
The Prime Minister’s official spokesman said: “On the wider issues that he’s raised, we introduced our unprecedented Covid support schemes at speed to protect jobs and livelihoods, helping millions of people across the UK, including nearly 12 million on the furlough scheme alone.
“We’ve always been clear fraud is unacceptable and are taking action against those abusing the system, with 150,000 ineligible claims blocked, £500 million recovered last year and the HMRC tax protection taskforce is expected to recover an additional £1 billion of taxpayers’ money.”