Boris Johnson has been interviewed as part of the investigation into partygate allegations as claims of another lockdown breach emerged, say reports.
The Prime Minister is said to have "shared what he knows" with senior civil servant Sue Gray for her inquiry into alleged parties in Downing Street and across Westminster.
It comes as she prepares to publish her report into claims of Covid rule flouting as soon as this week.
Explosive claims previously emerged that Mr Johnson attended a leaving do before Christmas 2020 during which he gave a speech to mark the departure of his defence adviser Captain Steve Higham.
That claim, revealed by the Mirror, is the latest in a long line of allegations about rule breaking in Downing Street, with Ms Gray looking into a litany of possible events.
These include a "bring your own booze" garden party during the first coronavirus lockdown that Mr Johnson has admitted he attended - although he insists he understood it to be a "work event".
Education Secretary Nadhim Zahawi insisted Mr Johnson was safe in his job after being repeatedly asked about his future.
Mr Zahawi said the Prime Minister had done the right thing by apologising - and added: "He's human and we make mistakes".
In a round of interviews on Monday, Mr Zahawi said he shared the public anger as his uncle had died of Covid-19.
And he told Sky News: "I can absolutely say to you that the Prime Minister feels the pain."
He said: "All I would say is we have to allow the investigation to take place. Why? Because that's the fair thing to do - you don't condemn a man without a thorough investigation."
The top Tory was asked three times if the PM was safe in his job by Today programme presenter Nick Robinson after six Tory MPs publicly demanded Mr Johnson quit.
Mr Zahawi finally said: "Yes, yes he is, because he is human and we make mistakes.
"He came to the despatch box and apologised and said he will absolutely submit himself to Parliament... when that report, that investigation is concluded."
Mr Johnson's sister, journalist and LBC presenter Rachel Johnson, told her listeners on Sunday that the Prime Minister was "completely compliant" with Covid rules whenever they met under restrictions.
Referring to the May 20 2020 BYOB event, she said: "To my mind, if he did go out into the garden, and he has told us he did, for him that would have been work."
In a bid to weather the partygate storm, reports suggested Mr Johnson could overhaul his top team.
This could see the likes of his principal private secretary Martin Reynolds, who sent an email inviting staff to enjoy the good weather in the No 10 garden in May 2020, being shown the door.
The Times said a bid to save Mr Johnson's premiership would include an announcement putting the military in charge of preventing small boats from crossing the Channel, as the Prime Minister looks to push "populist" policies.
A change being considered could, according to the newspaper, include processing asylum seekers in Ghana and Rwanda, although the Home Office would not be drawn on the suggestions.
Other touted policy announcements include attempts to reduce the NHS backlog and freeze the BBC licence fee for two years, with Culture Secretary Nadine Dorries hinting that the current model for funding the public broadcaster could be scrapped altogether.
It comes amid calls for the PM to quit, with a sixth backbencher, Tim Loughton, demanding that he resign, citing the "terminal damage" the revelations have done to his reputation.
Others, such as former party leader Sir Iain Duncan Smith, said it was for Ms Gray to determine what Mr Johnson knew about possible lockdown breaches in No 10, while newer MPs suggested the affair raised questions about the "moral authority" at the top of Government.
West Dorset MP Chris Loder, who was elected in 2019, told BBC Radio 4's Westminster Hour: "I'm not going to call for anyone's resignation until I've seen the facts, but then real action is required, and then we shall go from there."
Andrew Bowie, Conservative MP for West Aberdeenshire and Kincardine, said he would wait to read the conclusions of the investigation but admitted there was "a lot of ill-feeling out there and discomfort" on the Tory benches.
Former justice secretary Sir Robert Buckland - who was sacked from the Cabinet by the Prime Minister in September - told Times Radio that it would be "a bridge too far" for the No 10 incumbent if it emerged in Ms Gray's report that "people at the top of Government" were involved in "organising and planning and absolutely openly disregarding the rules".
