Dominic Cummings says evidence will show Boris Johnson “lied to parliament” when he denied knowing about the No 10 garden party, plunging his position deeper into jeopardy.
An email sent by “a very senior official” warned the “bring your own booze” event broke Covid rules, the exiled former chief aide claims – blowing apart the prime minister’s defence that he thought it was “a work event”.
In an explosive blog post, Mr Cummings wrote: “Not only me but other eyewitnesses who discussed this at the time would swear under oath this is what happened.”
The warning came after No 10 denied Mr Johnson was “warned about” a party, or that he told aides objecting to garden gathering that they were “overreacting”.
Many MPs believe Mr Johnson cannot survive in office if it is shown that he misled parliament with his repeated denials that parties took place with his knowledge.
But, in his post, Mr Cummings said that, after Mr Johnson’s private secretary Martin Reynolds sent the party invitation, “a very senior official replied by email saying the invite broke the rules”.
“This email will be seen by Sue Gray (unless there is a foolish coverup which would also probably be a criminal offence),” he has written – of the senior civil servant leading the investigation.
Mr Cummings claimed Mr Reynolds told him he would “check with the PM if he’s happy for it to go ahead”, on 20 May 2020.
“I am sure he did check with the PM. (I think it very likely another senior official spoke to the PM about it but I am not sure),” the post stated.
And it added: “The idea that the PPS [principal private secretary] would be challenged by two of the most senior people in the building, say he’d check with the PM then not – is not credible.”
Mr Cummings wrote: “The events of 20 May alone, never mind the string of other events, mean the PM lied to Parliament about parties.
“Not only me but other eyewitnesses who discussed this at the time would swear under oath this is what happened.”
The fresh allegations came as one senior Tory backbencher warned people are disinclined to let Mr Johnson off the hook for the rash of lockdown-busting parties.
“Right now, listening to the public who remember very well all the sacrifices they made, I think people may well be too angry to forgive,” former minister Steve Baker said.
Asked for the scale of the anger in his Wycombe constituency, Mr Baker replied: “Absolutely furious.”
Conservative MPs are contemplating the growing evidence that voters want Mr Johnson to quit, even before Ms Gray concludes her inquiry later this week or next week.
No 10 refused to say whether the prime minister has been interviewed by her, but said the “full” report will be published when it is ready – not just its key findings.
The allegation that Mr Johnson was warned that he should scrap the garden party was made first by his close friend Dominic Lawson, in a column for The Sunday Times.
Mr Lawson said an official also him that “at least two people” had alerted the prime minister that “this was “a party” and should be immediately cancelled”.
“I was told that Johnson’s dismissive response was to say they were “overreacting” and to praise Reynolds as “my loyal Labrador”,” the columnist wrote.
But, on Sunday, a No 10 spokesman said: “It is untrue that the prime minister was warned about the event in advance. As he said earlier this week, he believed implicitly that this was a work event.”
In his blog, Mr Cummings also said he expected the Gray inquiry would get to the bottom of his earlier allegation that he stopped Mr Johnson visiting the Queen “when he might have been infectious”.
“This episode was also witnessed by others who will tell the official inquiry that what I have said is true and the official denials are false,” he has written.
And he warned: “There are many other photos of parties after I left yet to appear. I’ll say more when SG’s [Sue Gray’s] report is published.”
The former aide also attacked Downing Street briefings about a “drinking culture” in No 10, arguing it was false and “intended to shift blame”.