Boris Johnson will be summoned to give evidence under oath on whether he lied over Partygate.
MPs today confirmed they will invite the Prime Minister for questioning just weeks after he resigns in disgrace on September 6.
And for the first time, Commons authorities confirmed the Prime Minister could face a by-election if he is found to have misled MPs.
The Privileges Committee, which is investigating whether the PM committed contempt of Parliament, released new details today.
For the first time the panel of seven MPs including four Tories confirmed: “The Committee will take oral evidence from Mr Johnson.
“At evidence sessions, Mr Johnson and any other witness may be accompanied by a legal or other adviser, and may take advice from them during the session, but must answer in person.”
Meanwhile Commons Speaker Sir Lindsay Hoyle confirmed that the committee's findings would fall within the remit of the Recall of MPs Act, following advice from a leading lawyer.
This means, if Boris Johnson was found in contempt and suspended from the Commons for at least 10 sitting days, he could be ousted from Parliament.
MPs who are suspended for at least 10 sitting days have a "recall petition" automatically triggered against them.
If at least 10% of local voters sign the petition, it automatically boots out the MP and triggers a by-election.
Boris Johnson could stand in that by-election to fight on as an MP.
But he could choose to resign from Parliament before the Privileges Committee even reports back in October or November - in which case he'd avoid any sanction.
No10 have refused to rule out this possibility.
The Committee today insisted its inquiry will go ahead despite Mr Johnson's resignation as Tory leader and his expected departure from No 10 in September.
The committee said "some have suggested" the inquiry is no longer necessary.
"Our inquiry, however, is into the question of whether the House was misled, and political developments are of no relevance to that.
"The House charged the committee with this task and we are obliged to continue with it."
At his final PMQs, Boris Johnson fired a parting shot at ex-Chancellor Rishi Sunak - when he said big infrastructure projects would not have been built "if we'd always listened to the Treasury".
The PM gave some "words of advice" to his successor including: "Cut taxes and deregulate wherever you can and make this the greatest place to live and invest, which it is".
Mr Johnson, who was brutally axed by his own MPs after months of scandal, offered his successor some advice: "Focus on the road ahead, but always remember to check the rear-view mirror".
Boris Johnson’s Press Secretary refused to rule out a comeback, after he said “hasta la vista” and “mission accomplished - for now”. She said it was “his way of saying farewell to his colleagues”.
Last week Boris Johnson was ordered to hand a vast cache of evidence to the probe into whether he lied to Parliament.
The Privileges Committee demanded diaries for the eight days he attended Covid lockdown-busting gatherings in Downing Street - which led to more than 100 fines from police.
MPs also ordered photos, internal notes, the PM’s briefing packs, e-mails, resignation statements and door logs - and warned the list could be expanded further at a later date.
Powerful chair Harriet Harman, the Labour veteran, set an August 15 deadline for No10 to serve up the documents - before Boris Johnson hands his resignation to the Queen on September 6.
And she ordered the nation’s top civil servant to let her committee visit 10 Downing Street, to “inspect” where the parties happened.
In correspondence last week, Ms Harman stressed she was not seeking to “attribute blame” to staff or former staff. She added witnesses who “wish to remain anonymous” can give evidence about whether the Prime Minister lied.
The Committee is investigating whether Boris Johnson committed contempt of Parliament by misleading MPs over what he knew about No10 parties.
Seven MPs, including four Tories, are probing the PM’s claims that “the rules were followed at all times” and he was “repeatedly assured there was no party”.
Mr Johnson's allies have moaned the probe will be a "kangaroo court".
The Privileges Committee can find MPs in contempt of Parliament for “deliberately misleading” the Commons - such as War Secretary John Profumo who denied an affair in 1963 - and recommend they are suspended.
Investigations are rare. The last MP to face any sanction was Tory Justin Tomlinson in 2016, and the last investigated for misleading MPs was Labour ’s Stephen Byers in 2006. He gave an inaccurate answer “inadvertently” so there was no contempt.
Previous chairman Chris Bryant, who recused himself, has said the MPs will only have to prove Boris Johnson "knowingly" misled Parliament, not that he deliberately did so.
Despite this, the word "knowingly" or "intentionally" do not appear in the motion.
Today's report said intent will not be relevant for considering whether there was a contempt of Parliamnent.
However, it added: "Intent has been considered relevant when a Committee has been considering whether or not there should be penalties for a contempt, or the severity of those penalties.
"It is best thought of as an aggravating factor in respect of remedy rather than a component part of the allegation."
That suggests if MPs prove Boris Johnson knowingly or deliberately lied it would be more likely to lead to him being suspended.
