Dominic Cummings has been told there are photographs of a party in Boris Johnson's Downing Street flat - and more pictures which will "incriminate" the Prime Minister.
The Prime Minister's former chief aide has alleged there are photographs of Boris Johnson at reported gatherings under investigation by police.
In a question and answer session on his paid-for blog, Mr Cummings was asked if there were photos that would "incriminate" the Prime Minister.
He said: "Yes there are photos of the PM at parties under investigation. Ive spoken to people who say theyve seen photos of parties in the flat."
He also claimed he had spoken to people who were in No 10 on November 13 2020, when there was an alleged gathering in Mr Johnson's Downing Street flat.
He said: "Ive talked to people who were in no10 on 13/11 who cd hear the party in no10 after I'd left - the press office is below the flat.
"If cops talk to people there that night, therell be witnsesses (sic) who say 'we could all hear a party with abba playing'."
He accused the PM of "lying" and added: "This could blow up terminally for him if lies to the cops but he wont be able to help himself other than say 'i dont remember' which is his default when he senses danger."
Mr Cummings said the chances of Foreign Secretary Liz Truss becoming Tory leader are "probably being overrated".
The Prime Minister's former top aide said the fact that "MPs are heavily influenced by polls" would "obviously benefit (Rishi) Sunak" in any future leadership race, and said Mr Sunak pro-Brexit stance would also help him.
He said Ms Truss was "little known" and had "said a lot of stuff that will not be popular with members if/when they hear it".
If she gets to the last 2, the combination of her support for Remain and her record will be big problems for her. Her chances are probably being "overrated," he said.
He said he thought Levelling Up Secretary Michael Gove "probably will" run again, while on Tory MP Tom Tugendhat, he said: "He has never been in Cabinet and it is hard to imagine Tory MPs promoting someone straight to the top job who has not been in Cabinet."
He said: "RS is obviously the front runner cos he's way ahead in the polls and unlike Truss/Hunt/TT was pro-Brexit.
"His team conceived and executed furlough in very tough circumstances, and which was one of most popular things a politician has done in a very long time. That will be a big strength when the contest comes."
He went on to tell Tory MPs there was "no excuse for self-delusions" about Boris Johnson.
"At this point the blame lies mostly with the Tory MPs", he wrote. "He's obviously totally unfit for the job and every day he's left their moral authority drops another notch."
But he added: "There's lots of blame to go around beyond them, including people in no10 who have also shown a distinct lack of moral courage..."
On Sue Gray limited report, he said: "So far as I know she's done a professional job in appalling circumstances."
