The Prime Minister has been fined by police despite giving assurances that Covid regulations were followed in No 10.
Sir Lindsay Hoyle said he had approved an application from Labour leader Sir Keir Starmer and other opposition MPs allowing them to table a motion for debate on Thursday.
It comes after the Prime Minister, along with his wife Carrie Johnson and Chancellor Rishi Sunak, were last week issued with fixed-penalty notices (FPN) by police investigating claims of coronavirus lockdown breaches in No 10.
Mr Johnson has apologised for his part in attending his own birthday bash, held in June 2020 in the Cabinet room, and paid the fine despite telling the Commons previously that all Covid guidance was followed at the heart of Government.
Sir Lindsay told MPs he had “no jurisdiction over the ministerial code” and whether it had been breached, but instead could “decide whether there is an arguable case to be examined”.
Having taken advice from clerks on the matter, the Speaker said he had decided to allow Sir Keir to table his motion.
Labour is understood to be wording the motion to make Thursday’s vote about whether to refer Mr Johnson to the Committee of Privileges, which examines issues relating to contempt of Parliament.
The committee, PA news agency understands, has the power to summon reports and documents.
It means that MPs could request to see the full version of senior civil servant Sue Gray’s inquiry into the Downing Street lockdown gatherings and any potential photographic evidence that exists.
The Prime Minister is scheduled to be on a Government trip to India later this week, meaning he will not be in Westminster for the vote on Thursday.
A Labour source: “Any Conservative MP considering voting to block this investigation would be voting for a cover-up.
“They should reflect on the mess they got themselves into over Owen Paterson before falling into line.”
Liberal Democrat leader Sir Ed Davey urged Conservative MPs to “do their patriotic duty” in Thursday’s vote.
The former cabinet minister said: “The country cannot afford a Prime Minister who breaks the law and lies about it, especially when families are facing a cost-of-living crisis.
“Johnson has taken the British people for fools for far too long, and it’s time for Conservative MPs to show where they stand.
“They must do their patriotic duty and kick Boris Johnson out of Downing Street once and for all.”
The ministerial code states that ministers who “knowingly mislead Parliament” will be expected to offer their resignation.
On December 1, the Prime Minister, addressing press reports about an alleged No 10 Christmas party in 2020, assured MPs that “all guidance was followed completely” in Downing Street.
But Mr Johnson has since been fined for the gathering on his 56th birthday, in which he was said to have been “ambushed” with a cake and up to 30 people attended, with the police investigation into other alleged breaches continuing.
The Conservative Party leader is alleged to have been at six of the 12 events being looked into by officers.
Downing Street said the decision to allow the vote on Thursday was “a matter for the Speaker”.
Northern Ireland Secretary Brandon Lewis, speaking to broadcasters on Tuesday morning, argued that Mr Johnson had not misled MPs as any updates given in the past he “believed to be the truth”.
Asked on Sky News whether Mr Johnson accepted that he broke the rules, the former Tory Party chairman replied: “In the sense that he has paid a fine that the police have decided to issue because the rules were broken.
“But that doesn’t mean that anything he said to Parliament was inaccurate at the time.
“What he said to Parliament he believed to be true at the time.”
Mr Lewis also appeared to suggest receiving a Covid FPN was similar to ministers having previously received speeding tickets or parking fines.
The Prime Minister is due to make a statement in the Commons on Tuesday and will, according to the Daily Telegraph, offer a “full-throated apology” to MPs following the announcement that he is among the 50-plus people fined so far as part of the Metropolitan Police probe into Covid breaches in Government.
But he is also expected to argue that there are bigger issues to focus on, with a need to deal with the crisis in Ukraine and unlawful migration following the announcement of a plan to send migrants, including those arriving by small boats, to Rwanda.