Allies of Rishi Sunak are furious over the former prime minister’s antics in recent days, which has seen him and his supporters raise doubts over the credibility of the Sue Gray inquiry, while openly questioning the privileges committee probe.
Tory MPs fear that Mr Johnson is “enough of an egomaniac” to force a division in the Commons on any sanction that the committee recommends should he be found to have knowingly misled parliament over Covid parties held in Downing Street.
It comes as Northern Ireland Secretary Chris Heaton-Harris took the extraordinary decision to unequivocally back Mr Johnson insisting he was “absolutely convinced” he did not intentionally mislead the Commons despite the inquiry still ongoing.
The issue is prompting senior backbenchers to warn that the ongoing scandal risks overshadowing the recent inroads made by Mr Sunak’s administration.
Tobias Ellwood, chair of the Defence Select Committee, told i Mr Johnson’s “antics are a threat to the party’s and Rishi’s efforts to succeed”.
“It’s a huge distraction,” he added.
Another Tory MP warned that Mr Johnson will try to force his supporters to vote against any sanction if he is found guilty, rather than the whole House accepting what the committee recommends.
The MP said: “He will try and force Tory MPs to decide whether they’re going to back the report and probably the position of the Government or whether they’re going to stand up behind him.
“I think that would be a huge mistake. But that’s exactly what I can see him doing because he doesn’t care about anyone other than himself.”
The backbencher added: “The bottom line is he couldn’t be trusted to tell the truth and he ran a really dysfunctional administration, we’ve now got a Prime Minister who can be trusted to tell the truth and is actually delivering stuff.”
Mr Johnson’s honesty was even called into question by the most senior civil servant, according to the latest leaks of Matt Hancock’s Whastapp messages, which showed Cabinet Secretary Simon Case describe him at the time as a “nationally distrusted figure”.
Despite this, Mr Heaton Harris launched a staunch defence of his former leader, stating he “does not believe for one second” that the former PM misled MPs.
Speaking on Sky News, he said Mr Johnson is “100 per cent” a man of integrity, adding: “I do not believe for one second Boris knowingly misled Parliament.
“I don’t think he will be found to have misled Parliament.
“In this country, you’re innocent until you’re proven guilty. I’m absolutely convinced Boris did not knowingly mislead Parliament.”
Despite Mr Heaton-Harris’s comments, who served under Mr Johnson as chief whip, a Cabinet Office spokeswoman would not be drawn on the issue, adding: “It would be inappropriate for us to comment given it is an ongoing and formal parliamentary process.”
The cross-party committee inquiry on Friday said the Commons may have been misled at least four times, with MPs set to cross-examine Mr Johnson later this month.
Mr Johnson has claimed the inquiry’s preliminary report showed he was being “vindicated”, while he and his allies have sought to cast doubt on civil service investigator Sue Gray’s own report into events in Downing Street following her surprise move to Sir Keir Starmer’s office.