oris Johnson will face a parliamentary investigation into whether he lied to MPs about Downing Street parties that took place during lockdown.
The prime minister will face a probe by the Privileges Committee after a Labour motion passed on Thursday without a vote or any objections.
It followed a U-turn by Downing Street who opted against tabling a delay amendment after it provoked a rebellion on the Tory backbenches.
MPs on the Committee will investigate whether Mr Johnson was in contempt of parliament when he told the Commons that “the rules were followed at all times” in No 10 during lockdown.
Mr Johnson was last week fined by the Met Police for attending his own birthday party in the Cabinet Room in June 2020 – in contravention of social distancing guidelines set by his own Government.
The probe will only begin after Scotland Yard has completed its own inquiry into Covid law breaches in Whitehall and No10. Mr Johnson has been linked to six of the twelve events being investigated by detectives.
As well as the police and parliamentary investigation, there has already been a review carried out of the partygate allegations by senior civil servant Sue Gray, who is waiting to publish her full findings.
Tory MPs were on Wednesday night ordered to back a Government amendment which would defer any decision on referring the matter to the committee until after the conclusion of the Met’s investigation and the publication of Ms Gray’s report.
But ministers ditched the amendment at the eleventh hour, fearing that it would give the impression that Mr Johnson was seeking to evade scrutiny. Mr Johnson later said he believes the House of Commons “should be able to do whatever it wants to do”.
A number of senior Tory MPs had been expected to rebel and abstain on the amendment delaying the vote. David Davis, the Conservative MP for Haltemprice and Howden, had confirmed to the Standard that he would have abstained had the amendment been tabled.
In another blow to the prime minister, influential Brexiteer MP Steve Baker withdrew his support and said he should be “long gone” during a debate on Labour’s motion on Thursday.
Speaking to MailOnline after the debate, he compared his role defending Mr Johnson’s actions to being the “lieutenant in the trenches doing all the s*** jobs” and said ministers must “rise to this moment” and oust the PM.
Mr Baker, who was influential in toppling former prime minister Theresa May over her Brexit deal, said Conservative politicians were being “dragged through the gutter”.
“It can’t go on”, he added.
His dramatic intervention came as Mr Johnson was greeted by Indian president Narenda Modi on a state trip.
Mr Johnson had been hoping to nudge forward negotiations on a post-Brexit trade deal between Britain and India, one of the world’s fastest-growing economies, and hinted more visas could be offered to Indian citizens as part of an agreement.
Speaking to BBC News at the Akshardham Temple in Ahmedabad, Mr Johnson branded the scrutiny over partygate as “not very useful” and said Mr Baker’s call for his resignation was “not the right thing to do”.
“There’s not a lot more I can say and what I want to do is focus on the things that I think are a massive long-term benefit to this country,” he added.
Sir Keir Starmer said that the U-turn showed that Mr Johnson had lost the support of Tory MPs who no longer wished to “go on defending the indefensible”.
“None of his MPs wanted to vote against the Labour amendment and I think the political mood changed today,” he added.
“I think the Prime Minister’s lost trust, I don’t think he has the moral authority to lead, and I think he should go.”
Separately, the Met Police said that they would give no further updates on the issuing of fixed penalty notices over partygate until after the local elections on May 6.
But in a later development, Downing Street indicated it would say whether Mr Johnson or Cabinet Secretary Simon Case are issued with fines, in the run up to the local elections.
A No 10 spokesman told reporters: “The Prime Minister himself said yesterday in Parliament that … if he were to receive another he would be transparent and would let people know. That hasn’t changed.”