Britain�s Prime Minister Boris Johnson looks on during a coronavirus briefing in Downing Street, London. (Photo by AP)

The British prime minister is reportedly set to face a major leadership challenge in his own party following a furious backlash over holding parties at his official residence during COVID-19 lockdowns.

Press reports suggested on Tuesday night that Conservative Party lawmakers angry at the so-called partygate scandal had been further enraged by Johnson�s insistence that nobody had told him a party at Downing Street would break the rules he had imposed himself.

Citing sources, the reports also emphasized that the required number of letters from fellow Tory lawmakers demanding a no-confidence vote in Johnson�s leadership could reach the 54 mark on Wednesday.

To trigger a leadership challenge, 54 of the 360 Conservative lawmakers in parliament must write letters of no confidence to the chairman of the party�s 1922 Committee.

The letters are confidential, so the chairman is the only person who knows how many lawmakers have actually written them.

The development came after Johnson denied an assertion by his former adviser that he had lied to parliament about one party, according to the unnamed sources.

The reports further note that as many as 20 Conservative lawmakers who won their seats at the last general election in 2019 plan to submit letters of no confidence in Johnson.

Just two years ago, Johnson was the darling of his party after he secured the biggest Conservative majority since Margaret Thatcher in 1987, allowing him to deliver on promises to finally steer Britain out of the European Union.

But his relationship is rapidly dissolving under the impact of a steady stream of revelations about Downing Street�s defying of strict lockdown rules.

Johnson, who was reported to have spent Tuesday evening in his Commons office meeting with potential rebels, apologized multiple times in a major broadcast interview for what he referred to as misjudgments that were made. However, he continued to insist that he had thought a bring your own booze party held in the Number 10 garden on May 20, 2020 had been a work event and he had not been warned about it in advance.

I do humbly apologize to people for misjudgments that were made but that is the very, very best of my recollection about this event, he claimed.

Nobody told me that what we were doing was against the rules, that the event in question was something that... was not a work event, and as I said in the House of Commons, when I went out into that garden, I thought that I was attending a work event.

Johnson further claimed he can�t imagine why on Earth it would have gone ahead, or why it would�ve been allowed to go ahead if he had been told it was anything but a work event.

Johnson�s former top aide Dominic Cummings cast doubt on that assertion on Monday, however, emphasizing that the prime minister knew that a drinks party held in his garden would break lockdown rules. Cummings further added that he would swear under oath that Johnson was told about the bash.

Johnson will address the parliament later on Wednesday. His Cabinet is expected to approve plans to end the recent restrictions imposed to tackle the surge of COVID-19 across the UK.

The Plan B measures were introduced by Johnson�s administration last month as the Omicron strain spread rapidly across the country. They included guidance to work from home where possible, masks for indoor settings, and vaccine passports for mass events.

The removal of the restrictions would reportedly satisfy many in his party who want to return to near normal life as Johnson seeks to contain a rebellion sparked by the partygate scandal.

Meanwhile, Deputy Labour Party Leader Angela Rayner has insisted that Johnson needs to go.

I think he�s trying to take the British public for fools. He�s not sorry that he clearly attended a party, knows it�s against the rules; he�s sorry he got caught for it, she emphasized in an interview with PA news agency.

I think people are incredibly frustrated, she added. He won�t, of course, and now it�s up to his MPs to do the right thing.