Boris Johnson deliberately misled parliament over Partygate, MPs find | Boris Johnson

Boris Johnson deliberately misled parliament over Partygate and was part of a campaign to abuse and intimidate MPs investigating him, a long-awaited report by the privileges committee has found.

In an unprecedented move, the cross-party group said he would have faced a 90-day suspension from the Commons had he not quit in rage at its findings last week.

Johnson was also found to have knowingly misled the committee itself, breached Commons rules by leaking its findings last Friday, and undermined the democratic processes of parliament.

As a result, it was recommended Johnson be banned from getting the pass granted to ex-MPs that allows them privileged access to the Westminster estate.

Johnson was originally set to face a suspension from parliament of 20 days – enough to trigger a recall petition that would have probably led to a byelection. But the committee said his blistering attempts to intimidate it last Friday would have ratcheted up the punishment to 90 days.

Two MPs on the committee – one Labour and the other from the SNP – had pushed for Johnson to be expelled from parliament. But the final report and sanction was signed off unanimously by all seven members.

“For the house to be given misleading information about the conduct of ministers and officials at the highest level of government, in the midst of the grave national emergency represented by the Covid-19 pandemic … is a matter of great seriousness,” the report said.

Retaliation by Johnson in trying to paint the committee as a kangaroo court “amounts to an attack on our democratic institutions”, it added.

Johnson rubbished the findings, accusing the committee members of trying to “bring about what is intended to be the final knife-thrust in a protracted political assassination”.

He said their findings were “preposterous” and a sign of “desperation”.

“This report is a charade,” Johnson said in a statement. “I was wrong to believe in the committee or its good faith. The terrible truth is that it is not I who has twisted the truth to suit my purposes. It is [the chair] Harriet Harman and her committee.”

Rishi Sunak dodged questions about the report, in a short interview on Thursday morning in the hours before its publication.

He denied he was “frustrated” by Johnson’s interventions over the past week, but refused to say whether the former prime minister should be allowed to stand again as a Tory MP.

Sunak added: “These are matters for the House of Commons, and parliament will deal with it in the way that it does.”

The moment is potentially one of major jeopardy for Sunak, given the fragile peace he sought to build in the Conservative party has fractured in recent days.

The row about the report has already resulted in Johnson sparking a difficult byelection next month by standing down and mounting furious attacks against one of the Tory committee members.

Over the following days, Tory MPs will have to decide how to vote on the report’s findings.

Many are likely to endorse the result of the more than year-long inquiry, but there could be a damaging split on the government benches if Johnson’s allies refuse to do so.