Dominic Cummings alleges lockdown party also held in Boris Johnson’s Downing Street flat

Claim comes amid controversy over a separate Downing Street Christmas party

Dominic Cummings has alleged a Downing Street flat party took place on 13 November when England was in the midst of a second Covid lockdown.

It comes after the prime minister ordered an investigation by the cabinet secretary — the most senior servant — into a separate party held before Christmas after footage emerged of No 10 staff joking about the event.

Posting on social media, the former senior No 10 adviser Mr Cummings said: “Will the CABSEC [cabinet secretary] also be asked to investigate the *flat* party on Fri 13 Nov, the other flat parties, & the flat’s ‘bubble’ policy…”.

The date identified by Mr Cummings was also the same day he left Downing Street with immediate effect after losing a power struggle and just eight days after the prime minister imposed England’s second national lockdown in response to surging Covid rates.

Asked by the Labour MP Catherine West whether there was a Downing Street party on 13 November during prime minister’s questions, Mr Johnson replied on Wednesday: “Mr Speaker, no, but I’m sure that whatever happened the guidance was followed at all times”.

Earlier, Mr Cummings also suggested the possible introduction of “plan B” Covid measures at a press conference later on Wednesday was to distract from the leaked video showing No 10 officials laughing about a banned Christmas party last December.

Addressing the incident in the Commons at prime minister’s questions, Mr Johnson apologised for the “offence” caused by the footage published by ITV News and claimed he shared the “anger of No 10 staff making light of lockdown measures”.

“I was also furious to see that clip, I apologise unreservedly for the offence it has caused up and down the country and the impression it gives,” Mr Johnson said.

But the prime minister still refused to admit a festive gathering had taken place at No 10. “I have been repeatedly assured since these allegations emerged that there was no party and that no Covid rules were broken.”

Mr Johnson added: “I’ve asked the cabinet secretary to establish all the facts and report back as soon as possible – if those rules were broken then there will be disciplinary rules.”

Downing Street later said it hopes the cabinet secretary’s investigation into the events of December 18, following allegations of a No 10 staff Christmas party, would be finalised “as soon as possible”.

“That will be an independent process carried out by Cabinet Office staff, under the leadership of the cabinet secretary,” the prime minister’s spokesperson told reporters.

Asked about the remit of Simon Case’s review, the spokesman said: “He has been asked to establish the facts on any events on (December) 18, and that’s what he will start work on.”

Pressed on how long the probe is likely to take, they added: “It is obviously rightly for them to dictate the timescale. I don’t have a set period but obviously we want it to be as soon as possible.”