BORIS Johnson is facing a fresh investigation into partygate with the Commons privileges committee now ready to launch a probe – but experts say this is unlikely to deliver the ‘killer punch’ to his premiership.

The Prime Minister has so far survived after being fined following a police investigation and a damning report by senior civil servant Sue Gray, which laid bare the extent of raucous behaviour in No 10 at a time when millions were forced to cut off contact with loved ones during Covid lockdowns.

However, discontent in the Tory ranks is growing, and the number of MPs who have publicly stated they no longer support Johnson currently stands at 23 – still short of the 54 letters required to trigger a confidence vote.

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While the Gray report was long-awaited, Thomas Caygill, lecturer in politics at Nottingham Trent ­University, said it did not reveal much more than was already known.

He said: “The main revelation to come from the report really was the photographic evidence that the ­parties had taken place.

“In some ways the report is ­probably more cautious than ­people were ­expecting, but it does tell us quite a lot about the culture in ­Downing Street at the time, which was certainly party related.

“That is concerning at any time ­really, regardless of whether there was a pandemic on or not – most workplaces don’t allow that kind of behaviour generally, and it is particularly not great given the pandemic.

“With the lockdown situation – millions of people up and down the country were obeying the rules, but the staff in Downing Street certainly weren’t. It just shows there was a lack of control really.

“That rests not just with Boris Johnson but also his senior advisers, his chief of staff and the senior civil servants and in the Cabinet Office as well.”

Johnson attempted to draw a line under the partygate scandal last week and shift the focus to the cost-of-living crisis, with Chancellor Rishi ­Sunak unveiling new policies to tackle rises in energy prices and inflation.

Caygill said Johnson had not emerged “unscathed”, with his ­approval rating hitting rock bottom – but it did look like he would survive as Prime Minister for the time being. “I think most other Prime Ministers would have resigned by now.”

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“But I think Boris Johnson’s ­position is he is fighting for survival and unless there is a constitutional mechanism to remove him, he is ­going to remain where he is – the norms and conventions aren’t going to be enough.

“It will have to be a hard and fast constitutional rule that ­removes him, whether that’s a general ­election which removes the ­Government from office or whether it is the ­Conservative Party triggering a vote of no confidence in his leadership.”

Chris Bryant, the chairman of the House of Commons Privileges Committee, has confirmed when he will stand down to allow an inquiry to go ahead into whether the Prime Minister lied to Parliament over partygate.

He has summoned the committee to a meeting on June 7 to finalise ­business before a new head is elected.

If the Privileges Committee finds Johnson in contempt of Parliament, it could recommend he is forced to apologise, suspended from the ­Commons, or even expelled.

Caygill said it would be unlikely to deliver a “killer punch” to Johnson’s premiership, pointing out it is a cross-party committee with Conservative MPs which will have to reach a ­consensus.

He added: “The other factor too is while they can suggest sanctions against the Prime Minister, the ­entire House of Commons will have to vote on and approve those sanctions ­before anything would happen.

“I think in the past, the worst they have done is given a couple of days suspension from the House of ­Commons.

“A Prime Minister being suspended from the Commons for bad ­behaviour would normally be a resignation ­matter, but [if[ it comes back for ­Johnson, he will have to be removed from office. He is not going to go ­voluntarily.”

Chris Stafford, a doctoral ­researcher in the politics and ­international relations department at the University of Nottingham, said one issue would defining that he “misled” parliament.

He said: “I think the majority of people believe that he did deliberately mislead Parliament and the nation, but actually proving this is a different matter.

“Since the story first broke all those months ago, Johnson has been deliberately ambiguous in his denials.

“He claimed there were no parties, but he can wriggle out of this because he claims he saw them as work events.

“He claimed no rules were ­broken, but can get out of this by again claiming he believed this and others ­assured him it was the case.

“Johnson has always given himself enough wriggle room to plant doubt and make it hard to prove he was ­deliberately lying.

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“The committee might find there is enough evidence to prove he was ­lying, but as things stand it is ­probably a long shot.”

Stafford said while the Tory leader’s position was quite unstable prior to the report, in “true Johnson style” he has managed to hang on through “a combination of obfuscation and ­delaying tactics”.

He added: “Nonetheless, I think his reputation is tarnished beyond repair with the public and he risks dragging his party down with him.

“But Johnson is unlikely to resign. He spent years manoeuvring his way into No 10 and he will not give up ­office willingly.”

Stafford said the Conservative ­Party may keep him in position for now, because there aren’t many ­“viable candidates” to replace him.

“The looming by-elections will ­perhaps sway some MPs if they go very badly for the Conservatives, while a substantial and sustained drop in poll ratings may add to this,” he added.

“But as things stand, Johnson will likely cling on for a bit longer yet.”