During a stormy session in the Commons, Johnson was warned he has lost the support of a senior Tory MP over the handling of the allegations.

Former cabinet minister Andrew Mitchell said he had previously given his “full-throated support” to the PM over a 30-year period.

But Mitchell became the latest Tory MP to publicly question Johnson as he said: “I have to tell him he no longer enjoys my support.”

Meanwhile, Conservative former prime minister Theresa May said: “The Covid regulations imposed significant restrictions on the freedoms of members of the public. They had a right to expect their Prime Minister to have read the rules, to understand the meaning of the rules and indeed those around him to have done so too and to set an example in following those rules.

“What the Gray report does show is that Number 10 Downing Street was not observing the regulations they had imposed on members of the public, so either my right honourable friend had not read the rules or didn’t understand what they meant and others around him, or they didn’t think the rules applied to Number 10. Which was it?”

Johnson replied: “No, Mr Speaker that is not what the Gray report says, I suggest that she waits to see the conclusion of the inquiry.”

Former chief whip Mark Harper was among the Tory backbenchers to ask for Johnson to commit to publish Gray’s report in full once the police investigation has concluded.

He noted: “Many have questioned, including my constituents, the prime minister’s honesty, integrity and fitness to hold that office. In judging him he rightly asked us to wait for all the facts.”

Johnson replied: “What we’ve got to do is wait for the police to conclude their inquiries, that is the proper thing to do. People have given all sorts of evidence in the expectation that it would not necessarily be published, at that stage I will take a decision about what to publish.”