Boris Johnson deliberately misled parliament multiple times about lockdown-breaking parties in Downing Street, MPs have found.
The cross-party inquiry also found the former prime minister was complicit in a campaign of abuse and intimidation against the MPs investigating him.
The Privileges Committee said Johnson knowingly misled the House of Commons over his claims that he followed Covid-19 rules, committing “serious contempt”.
It found it was “unlikely on the balance of probabilities that Mr Johnson, in the light of his cumulative direct personal experience of these events, could have genuinely believed that the rules or guidance were being complied with”.
The committee, comprised of four Tories, two Labour MPs, and one from the SNP, found he misled the House in five ways with his Covid-19 assurances and had been “disingenuous” with their investigation multiple times.
And it said he committed further contempt by undermining the democratic processes of the House of Commons.
The committee said in the report: “We came to the view that some of Mr Johnson’s denials and explanations were so disingenuous that they were by their very nature deliberate attempts to mislead the committee and the House, while others demonstrated deliberation because of the frequency with which he closed his mind to the truth.”
It added: “The contempt was all the more serious because it was committed by the prime minister, the most senior member of the government.
“There is no precedent for a Prime Minister having been found to have deliberately misled the House.
“He misled the House on an issue of the greatest importance to the House and to the public, and did so repeatedly.”
Last week, Johnson quit as an MP with immediate effect after being given an advanced copy of the committee’s findings.
Published in a scathing 30,000-word report here, it had recommended that Johnson be suspended for 90 days, far exceeding the amount needed to trigger a by-election.
Following his resignation, MPs recommended Johnson should not be granted a former members’ pass, which allows ex-MPs limited access to parliament.
The report rejects Johnson’s claims that some of the gatherings were necessary for work purposes.
“A workplace ‘thank you’, leaving drink, birthday celebration or motivational event is obviously neither essential or reasonably necessary,” it said.
“Mr Johnson is adamant that he believed all of the events which he attended and of which he had direct knowledge were essential. That belief, which he continues to assert, has no reasonable basis in the rules or on the facts.”
Johnson has attacked the Westminster committee as a “kangaroo court” whose purpose is to “find me guilty, regardless of the facts”.
He hit out at what he called a “deranged conclusion”, accusing the Tory-majority group of MPs he has repeatedly sought to disparage of lying.
He said: “The terrible truth is that it is not I who has twisted the truth to suit my purposes, it is Harriet Harman and her committee.
“This is a dreadful day for MPs and for democracy.
“This decision means that no MP is free from vendetta, or expulsion on trumped-up charges by a tiny minority who want to see him or her gone from the Commons.
“I do not have the slightest contempt for parliament, or for the important work that should be done by the Privileges Committee.
“But for the Privileges Committee to use its prerogatives in this anti-democratic way, to bring about what is intended to be the final knife-thrust in a protracted political assassination – that is beneath contempt.”
The Privileges Committee has been investigating Johnson for almost a year.
It can make recommendations on sanctions but the Commons must vote on whether to accept them.