Boris Johnson was facing renewed anger from MPs and bereaved families on Monday after the disclosure that his fiancee threw him a surprise lockdown birthday party, as sources said an official inquiry had uncovered “appalling evidence of mismanagement” at the heart of Downing Street.
Sue Gray, the senior civil servant leading the inquiry into Downing Street parties, is expected to make deeply critical recommendations on overhauling No 10’s operation after hearing of repeated failures of leadership, according to a Whitehall source who spoke to the inquiry.
In the latest alleged breach of rules, No 10 admitted that Carrie Johnson held a party for the prime minister and up to 30 staff on 19 June 2020 despite Covid rules banning indoor social gatherings. Outdoor gatherings were limited to groups of six.
ITV reported that the prime minister attended the party in the cabinet room at No 10 at 2pm on his 56th birthday, and that the interior designer Lulu Lytle – who was not a member of No 10 staff – was there.
The room was said to have been laid out with Marks & Spencer party food and a birthday cake, with staff singing “Happy Birthday” and staying for 20-30 minutes.
No 10 said the PM attended for 10 minutes and denied reports from ITV that he held a party later on 19 June in his Downing Street residence. Gray is understood to have already been told about the allegations, meaning the latest exposé is unlikely to delay publication of her report, expected late this week.
A spokesperson for Lytle said she was working on the controversial refurbishment of Johnson’s flat that day, adding: “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.”
It comes as whips have been warned that Johnson is facing the possibility of losing a vote of no confidence amid growing anger about the multiplying revelations.
One senior MP estimated up to a third of the ministerial payroll – ranging from ministers to parliamentary private secretaries and Tory vice-chairs – could vote against the prime minister, leaving Johnson reliant on support from at least half of his backbench MPs.
On Monday night angry MPs said they were fuming at the latest “drip-drip” of lockdown breach stories. “And presumably there is more being stored up for release after the Gray report just in case that hadn’t dealt the killer blow,” one said.
Another Tory MP who has not yet submitted a no confidence letter said the birthday gathering was “clearly social” and “changes things – a lot”.
The Guardian understands that Labour is poised to attempt to force the publication of the full Gray report at its opposition day debate next week, should No 10 attempt to hold back the full details and only publish summary findings.
A frontbencher said those who had been running the numbers of would-be rebels for the prime minister over the weekend were becoming increasingly concerned that Johnson could lose a no confidence vote despite multiple charm offensive calls to wavering MPs.
“People have been telling them over the weekend that they are behind the PM, but of course, that could be people lying,” the source said.
“Ultimately there’s a third of the payroll I could see voting against the PM – if that happens he needs at least half of all backbenchers to back him. That seems pretty unlikely. You can see things get dangerous quickly.”
Most MPs are still determined to wait for the outcome of Gray’s inquiry, expected late this week.
Johnson is alleged to have also hosted family and friends later that afternoon in his home but No 10 denied this, claiming he hosted a small number of relatives outside only.
Regarding the 2pm gathering, a No 10 spokesperson 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 10 minutes.”
Addressing the later alleged party in the flat, a spokesperson said: “This is totally untrue. In line with the rules at the time, the prime minister hosted a small number of family members outside that evening.”
On Monday, Dominic Cummings, the prime minister’s former chief adviser, said he had handed written evidence to the Gray inquiry – but warned that some staff were concerned about handing over evidence, fearing retribution from the prime minister.
Gray has reassured some staff they would be given a degree of protection, the Guardian understands. However, one source who has given evidence to the inquiry said fears of retribution persisted. “Junior staff have been concerned if they are seen to corroborate what’s in the press,” one Whitehall source said.
“People have been burnt as well by the Priti Patel investigation, where the advice was suppressed and the conclusion wasn’t followed. It’s one thing to be asked and not lie and quite another to offer the evidence proactively.”
Labour demanded in a letter to Johnson that he stand by his assurance in parliament on 8 December to place a copy of the report – then being compiled by cabinet secretary Simon Case – in the Commons library for all MPs to see.
Deputy leader Angela Rayner said the government “cannot allow any further cover-up” and urged Johnson to give MPs an embargoed copy of the report to let them read the detail before quizzing him in parliament.
Tory MPs said that there would be outrage among backbenchers should there be any attempt to censor the findings. Another said: “The only reason you would hold it back is because you’ve calculated that whatever’s in there is worth taking the flak for trying to hide it.” A third said: “The more that’s withheld, the less likely it is to be accepted.”
Labour could also table a “humble address” motion to force the government to publish the report in full, or parts of the evidence to ensure any testimony of criminality has been passed to the police.
However, if the government pulls Labour’s next opposition day debate, other options being considered are using a select committee to request documents.
Scotland Yard reiterated its previous statement, saying if Gray’s inquiry finds evidence of a potential criminal offence then officers will make a “further consideration” on whether to investigate.
Reacting to the birthday party revelations on Monday, Jo Goodman, cofounder of Covid-19 Bereaved Families for Justice, said: “Like thousands of others, I remember 19 June 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’s completely sickening that the prime minister spent [time] sharing cake with 30 friends indoors … every day and every fresh scandal pours salt on the wounds of the hundreds of thousands who have lost loved ones. If he had any decency he would do what we and the country is calling for him to do and go.”
• This article was amended on 25 January 2022. A sentence about Conservatives who might vote against the prime minister meant to include some parliamentary private secretaries, not “principal private secretaries”, who are civil servants.
