London(CNN) Boris Johnson will face a third investigation into whether he knowingly misled parliament when he denied that any rules were broken in Downing Street after stories emerged of lockdown breaking parties and gatherings taking place during the Covid-19 pandemic.
A motion tabled by the opposition parties was passed without a vote on Thursday after the British prime minister and his government whips gave their Conservative members of parliament the option not to vote on the motion, meaning it passed without opposition.
Johnson himself has received a fine from London's Metropolitan Police for attending a gathering on June 19, 2020, and numerous fines have been issued for a number of events that took place during national restrictions.
The thrust of Johnson's defense is that he wasn't aware of any lawbreaking when he made the statement to parliament; therefore he could not have knowingly misled lawmakers. The UK's ministerial code says that if government ministers knowingly mislead parliament, then it is expected that they will resign from their post.
Thursday's motion, tabled by opposition parties to refer Johnson to a parliamentary committee, was passed after the government dropped its amendment to delay the vote and allowed Conservative MPs a free vote.
This was seen as a major U-turn and a sign of how much Johnson's support has fallen among his own rank and file, allowing Conservative MPs to simply not vote, rather than have to defy the whip and spare Johnson the humiliation of a rebellion.
However, Johnson was not spared total humiliation: Steve Baker, one of his most loyal supporters who campaigned for Johnson to become Conservative leader in 2019, on Thursday called for the Prime Minister's resignation. Baker told Parliament that he would vote for the motion, but added "really, the Prime Minister should know the gig's up."
Baker is an influential figure among Conservative MPs, especially among the Brexiteer wing of the party, which backed Johnson in the past.
The parliamentary investigation will not take place until the police investigation into Downing Street parties has concluded and a full report, written by senior civil servant Sue Gray on the so-called "Partygate" scandal, is published.
The committee that will carry out the investigation will be able to write up recommendations, including suspending Johnson from parliament, which would then be subject to a parliamentary vote. It's unclear how realistic this outcome is, given the committee carrying out the investigation is made up of mostly Conservative lawmakers and Johnson still has a relatively large majority in parliament.
That said, if things reach this point then it's possible that further damning information will have been revealed in Gray's report or that Johnson receives further fines from the police. In that event, it will be up to Conservative MPs to decide whether they want to call a confidence vote in his leadership.
Johnson will lead the Conservative party at local elections next month and the result of those elections could also play into decisions on whether or not he should be removed by his own party. The Partygate scandal has seriously damaged the Conservative's poll ratings and undermined Johnson's own popularity.