Dominic Cummings has redoubled his criticism of his old boss Boris Johnson, saying the PM cannot distinguish “between truth and lies”.
The former top adviser said Mr Johnson “lies so blatantly, so naturally, so regularly” that he sees “no real distinction”.
In a blog post, Mr Cummings claimed Mr Johnson “regularly admits it’s ludicrous he’s prime minister”.
The PM’s official spokesman rejected the former aide’s claims about lying.
“I don’t plan to engage with every allegation made,” he added when asked about the blog by reporters on Monday.
It is the latest broadside against the PM from Mr Cummings since he was forced out of his No 10 role last year, following an internal power struggle.
But the former aide also defended his decision to join Mr Johnson’s top team in 2019, despite believing him “unfit to be PM”.
In a post to paying subscribers to his Substack website, Mr Cummings claimed Mr Johnson “regularly admits it’s ludicrous he’s prime minister”.
He wrote that the PM is “hopeless at bureaucratic infighting,” and “routinely says and does things so foolish that people are open-mouthed”.
Mr Cummings added he knew Mr Johnson was “in any objective sense, unfit to be PM” when he agreed to become his senior adviser in summer 2019.
‘Even bigger disaster’
But despite this, he added, he and former members of the Vote Leave campaign decided to “roll the dice” and join his No 10 team anyway, believing his defects could be “partly mitigated” in office.
He added that they also believed that, without their help, the Conservatives would fail to resolve the post-referendum “constitutional crisis”.
This, he wrote, could have led to a second referendum and former Labour leader Jeremy Corbyn winning power, which would “probably be an even bigger disaster”.
He also justified the move as a chance to deliver post-Brexit political reforms, adding they thought Mr Johnson’s weaknesses could be “turned to advantage”.
He wrote that Mr Johnson’s “ignorance of Whitehall” and his “desire to enjoy himself rather than work hard” provided a “very weird opportunity to force through certain important things that the system left to itself won’t do”.
“Precisely because he doesn’t know what he’s doing, we may be able to get him to agree things ‘the system’ will think are ‘extreme’ but we think are necessary,” he added.
“As often in politics the immediate prospect of a second referendum and Corbyn – with all the misery, poverty and damage to democracy this would bring – outweighed calculations about the distant future.”