Boris Johnson has once again apologised over the Partygate scandal, this time for “inadvertently misleading” the British Parliament over the COVID law-breaking parties at Downing Street during his time as prime minister.

Johnson was grilled for hours on Wednesday by the House of Commons Privileges Committee, which is investigating whether he knowingly misled the Parliament over the Partygate scandal of gathering that breached the lockdown rules.

“I apologise for inadvertently misleading this House, but to say that I did it recklessly or deliberately is completely untrue, as the evidence shows,” he told the committee.

During a heated session, the 58-year-old senior Conservative Party MP insisted the events that came under the purview of the scandal were “essential” during the lockdown period as Downing Street doubles up as a workplace and residence.

"I believe it was absolutely essential for work purposes," he said when questioned about a particular event in November 2020.

Johnson said the meeting, which happened while social distancing rules were in place, was "necessary" because two senior members of staff were about to leave "in potentially acrimonious circumstances".

"I accept that perfect social distancing is not being observed but that does not mean that what we were doing is incompatible with the guidance," he said.

In his opening remarks, Johnson swore "hand on heart, I did not lie to the House" after taking an oath on the Bible to tell the truth during the session.

He said: "When this inquiry was set up I was completely confident that you would find nothing to show that I knew or believed anything else, as indeed you have not.

"I was confident, not because there has been some kind of cover-up. I was confident because I knew that was what I believed and that is why I said it." The former prime minister insisted time and time again during the grilling that his officials assured him no rules were being broken and nobody raised any problems with him.

But he admitted it had been a mistake to tell the Commons that guidance had been "followed completely" at No. 10 Downing Street.

"I was misremembering the line that had already been put out to the media about this event, which was 'COVID rules were followed at all times'," he said.

Johnson has previously apologised to Parliament for party gate after he was issued with a fine by Metropolitan Police, saying the buck stopped with him as the prime minister.

During the oral evidence to the cross-party committee, he said it was difficult to social distance at No. 10 Downing Street as it is a "cramped, narrow 18th Century townhouse" and they had no choice but to meet "day in, day out, seven days a week in an unrelenting battle against COVID".

"I will believe till the day I die that it was my job to thank the staff for what they had done, especially during a crisis like COVID, which kept coming back, which seemed to have no end," he said, with reference to the so-called farewell events for staff over the lockdown period.

During the three-hour session, there were moments when Johnson lost his cool. When asked if he sought further advice over the issue, Johnson reacted: "This is complete nonsense, I mean, complete nonsense. "I asked the relevant people. They were senior people. They had been working very hard." But the chair of the committee, veteran Labour MP Harriet Harman, called his reassurances “flimsy” and "did not amount to much at all".

The committee is expected to take weeks before it concludes its inquiry, with further written and oral evidence also likely. It will then present its findings to Parliament and it will be for MPs to vote on the action to be taken.

If a suspension of 10 days or more is proposed by the committee and voted through by MPs, a by-election may have to take place in Johnson’s Uxbridge and South Ruislip constituency in London.

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