Boris Johnson was thrown a surprise birthday party by wife Carrie during the first Covid lockdown despite indoor social events being banned, it was claimed tonight.
The latest revelation threatens to blow apart his attempts to shore up support among mutinous Tory MPs who are already plotting his downfall.
More than 30 officials gathered for the PM's birthday bash in the Cabinet Room for up to half an hour in the afternoon of June 19, 2020, according to ITV News.
Mrs Johnson led the staff in a chorus of happy birthday while the PM was presented with a cake, before tucking into picnic food from M&S.
Those who lost loved ones to Covid, some separated due to lockdown rules, slammed the PM's party - branding it "disrespectful".
Francis Goncalves' mum, dad and brother died within seven days after catching Covid.
With such a painful experience of the pandemic, Francis said he was taken aback when he heard rumours of a Downing Street party happening in May 2020, before Boris Johnson apologised and confirmed he was present.
"If you're going to create a rule, stick by it," he said. "It shouldn't be a situation of 'do what I say, not as I do'. It's not just a kick in the teeth, it's so unprofessional and disrespectful to everyone.
"Is he going to resign? Is he going to stay on? Who know's what's going to happen, but he's completely undermined the entire process of trying to protect people. People are now turning around and asking 'have you been spreading a lie?', 'Is this all just some sort of charade?', 'what's going on?'. The rules were necessary, but there are a lot of very angry people out there.
"Everyone wants to see their family members and because of these restrictions, [many] lost the opportunity to see family members. Rather than actually being there and seeing what your family had been going through, you were only able to see them via a phone call or video call."
Jane Smith, 66, slammed Boris Johnson after being limited to just 20 minute long Skype calls with her mother who passed away last year.
Jane's mother Rita died in May last year in a care home near Bristol, at the age of 95, the same time Downing Street officials were accused of throwing illegal garden parties.
She shared a heartbreaking video on social media of one of her limited Skype calls with her deteriorating mother which she described as "barbaric and inhumane."
Jane from Thornbury, South Gloucestershire, said: "I've got no nice words to describe Boris Johnson.
"He sets the rules for everyone else yet doesn't follow them himself.
"He said nobody told me the rules, but he should know as the Prime Minister what you can and can't do better than anyone.
"I am speechless with anger, especially when people are having parties and I didn't have free access to my mum, even when she was dying."
Lisa Catherine: "Apparently Boris had a birthday tea 19th June, 2020 - 7 days later we had our daughter's birthday tea in the garden with no hugs, no cake blowing and just for two hours. How stupid were we."
Officials said to have been present at the party included Martin Reynolds, the most senior civil servant in the PM's office, who sent the explosive 'BYOB' party email.
Interior designer Lulu Lytle, who was not a member of staff but was renovating the Downing Street flat at the time, was also present.
No 10 did not deny the event took place, but claimed the Prime Minister only attended briefly.
A No 10 spokesman said: "A group of staff working in No 10 that day gathered briefly in the Cabinet Room after a meeting to wish the Prime Minister a happy birthday.
"He was there for less than ten minutes.”
Later that evening, the PM and his wife were said to have hosted family friends in their residence upstairs in an apparent further breach of the rules.
But Downing Street denied the claims - claiming the PM hosted a small number of family members outside instead.
Labour leader Keir Starmer said: “This is yet more evidence that we have got a Prime Minister who believes that the rules that he made don’t apply to him.
"We cannot afford to go on with this chaotic, rudderless Government.
"The Prime Minister is a national distraction and he’s got to go.”
The week before his birthday party, Mr Johnson had asked the rest of the country to stick to the guidance in a Downing Street press conference.
On 13 June, 2020, the Queen watched a scaled back ceremony for her official birthday on her own, without family by her side.
And in March 2020, the PM replied to a letter from 7-year-old Josephine Booth who cancelled her own birthday party, telling her "we all have got to do our bit".
Senior civil servant Ms Gray is expected to publish her report into Downing Street parties later this week.
Dominic Cummings has refused to be interviewed by the inquiry, claiming the PM would "lie and confuse everybody" if he did, and agreed to submit written evidence instead.
He claimed that No 10 staff were scared to hand over evidence to the inquiry out of fear the PM will "see everything" - so would leak details after it had concluded.
The PM's former chief adviser, now a fierce critic, warned that “other damaging stories” would emerge unless Tory MPs forced Mr Johnson from office.
Writing on his blog, he added: “I know others are very worried about handing things to the Cabinet Office because they know the PM will see everything SG collects.
"This inevitably means that evidence, including photos, is not given to her and instead will keep leaking after her report."
It follows Downing Street police giving "extremely damning" evidence to the inquiry, raising further questions over why Scotland Yard has so far failed to investigate.
Metropolitan Police chief Dame Cressida Dick will come under pressure at a London Assembly hearing on Tuesday over her decision.
However, Met Police officers who guard the Downing Street gates were said to have been "only too willing" to cooperate with the inquiry.
Sources claimed they had been able to provide "lots of information" about lockdown-busting events at No 10 .
One told the Daily Telegraph: "Put it this way, if Boris Johnson is still Prime Minister by the end of the week, I'd be very surprised".
The Mirror has been told that No 10's internal security staff - known as custodians - warned staff on a handful of occasions that their lockdown partying was getting out of hand.
It comes after the PM's spokesman pointedly refused to say that Ms Gray's whole report will be published - saying it will be down to Mr Johnson how much is released.
Two cabinet ministers have said only the “findings” of the report will be published.
Ms Gray's inquiry is understood to have been widened to cover claims of parties in the Downing Street flat the PM shares with wife Carrie.
The Mirror first revealed the allegations - denied by No 10 - when we blew open the whole 'Partygate' scandal last November.
Sources told us there were “always parties” in the flat Mr Johnson shares with wife, adding: “Carrie’s addicted to them”.’
Mr Johnson has signalled his defiance and has reunited the team who helped him win the Tory leadership - nicknamed 'the Avengers' - to win back support among rebellious MPs.
But many Tory MPs are holding off sending a letter of no confidence in the PM until the results are unveiled.
No 10 has asked Commons Speaker Lindsay Hoyle if he can make a statement "almost immediately" after the report is released so he can take charge of the narrative.
Mr Johnson is also facing a row over Government whips handling of the row, with senior Tory MP William Wragg discussing "blackmail" claims with Scotland Yard.
Jo Goodman, co-founder of Covid-19 Bereaved Families for Justice, said "Like thousands of others, I remember June 19 vividly. It was the day before what would have been my Dad’s 73rd birthday, shortly after he had passed away from Covid-19. It was a horrible time for my family, but we stuck to the rules, not even being able to hug to comfort each other.
"It’s completely sickening that the Prime Minister spent [it] sharing cake with 30 friends indoors and though we’re not even surprised any more, it still brings fresh pain. Whilst dozens sang happy birthday to him, families couldn't even sing in memory at their loved ones funerals.
"Regardless of any report, the Prime Minister clearly needs to resign. He’s lost all credibility."
A spokesman for Ms Lytle said: “Lulu was present in Downing Street on 19 June working on the refurbishment.
"Lulu was not invited to any birthday celebrations for the Prime Minister as a guest.
"Lulu entered the cabinet room briefly as requested, while waiting to speak with the Prime Minister.”