Johnson claims public ‘don’t give a monkey’s’ about Cummings’ comments

He also claimed Johnson had attempted an “unethical, foolish, possibly illegal” plan to get Tory donors to fund the lavish refurbishment of his official Downing Street flat.

The claims prompted speculation Cummings is bent on revenge after his dramatic departure last year from No 10 amid a bitter internal power struggle with Symonds.

Ministers are braced for further allegations when he appears next month before MPs investigating the government’s response to the coronavirus pandemic.

Johnson sought to brush off the charges saying the public did not “give a monkey’s” about such matters.

Asked by LBC radio if he had tried to block the leak inquiry, the prime minister replied: “No, of course not.”

Downing Street said in a statement that ministers had acted at all times “in accordance with the appropriate codes of conduct and electoral law”.

Labour said the Tories were fighting “like rats in a sack” demonstrating a “breath-taking contempt” for the public.

In a lengthy blog post Cummings accused ]Johnson of ordering his aides to make false allegations about him and offered to give evidence to the cabinet secretary Simon Case.

He went on to deny a No 10 claim that he was the so-called “chatty rat” responsible for the leak last October which was seen to have “bounced” the government into announcing a second lockdown.

He said Case had told both him and Johnson that “all the evidence” pointed to Henry Newman, a special adviser and a close friend of Symonds, and “others in that office” as having been responsible.

The prime minister, he said, had been “very upset” as it would cause him “very serious problems” with Symonds if Newman had to be fired and had asked whether the leak inquiry could be stopped.

Cummings said he told Johnson that was “mad” and “totally unethical” and that he could not cancel an inquiry into a leak which had affected millions of people “just because it might implicate his girlfriend’s friends”.

“It is sad to see the PM and his office fall so far below the standards of competence and integrity the country deserves,” he said.

Johnson, who spent Friday campaigning in Hartlepool by-election, insisted he was concentrating on protecting the health of the public, adding: “I don’t think people give a monkey’s about this issue”.