Boris Johnson will be investigated over claims he misled Parliament about lockdown parties

The Labour-led motion, which called for the Committee for Privileges and Conduct to launch an investigation, passed without a vote yesterday after receiving no objections, while the Prime Minister was away on an official trip to India.

The probe, which is expected to include public hearings, will begin after The Metropolitan Police has completed its own inquiry into lockdown-breaking parties in Downing Street and Whitehall.

It comes after Mr Johnson and Chancellor Rishi Sunak received fixed penalty notices from Scotland Yard last week, for attending a 56th birthday gathering for the Prime Minister at No 10 in June 2020.

The Government said it would order Tory MPs to delay the vote on the inquiry, until the police probe is over and Sue Gray’s long-awaited report is published, but then scrapped that plan yesterday morning and agreed to allow a free vote.

A number of influential Tories condemned Mr Johnson’s actions during the debate, including former minister Steve Baker who said the Prime Minister should “know the gig’s up” and be “long gone”.

William Wragg, chair of the Public Administration and Constitutional Affairs Committee, called on the Prime Minister to resign and said “it is utterly depressing to be asked to defend the indefensible”.

The Tory MP, who has submitted a letter of no confidence, also said his Conservative colleagues “must be seen to do the right thing” and back the investigation, to maintain the trust of voters.

“We each only have our own limited and imperfect integrity. We can’t keep spending it on others who we cannot be sure will not let us down,” he said.

However, several MPs, including Yorkshire’s Alexander Stafford, spoke in defence of the Prime Minister.

The MP for Rother Valley, said Mr Johnson gave a “heartfelt apology” to the House of Commons “at the earliest opportunity”, after he was fined by police, and it is time to move on and “crack on with the priorities of this country”.

He also said it is “unfathomable” that the Prime Minister would have knowingly broken the law, as he told journalists about his birthday celebrations at the time and details were published in a newspaper the following day.

Labour leader Keir Starmer said the Prime Minister had been accused of “repeatedly, deliberately and routinely” misleading the House of Commons about illegal gatherings in Downing Street and if the allegations are proved, he would be held in contempt.

“After months of denials, of absurd claims that all the rules were followed, feigned outrage at his staff discussing rule breaking, we now know the law was broken,” said Mr Starmer.

“We know the Prime Minister himself broke the law and we know he faces the possibility of being found to have broken it again and again and again.”

He added: "The convention that Parliament must not be misled and, in return, we do not accuse each other of lying are not purist quirks of this place, they are fundamental pillars on which our constitution is built and they are observed wherever parliamentary democracy thrives."

But the Prime Minister insisted he has “absolutely nothing, frankly, to hide” when he spoke to the media during his visit to Ahmedabad and said he remains confident of leading the Tories into the next general election.