Dominic Cummings predicts Downing Street exit for communications chief Jack Doyle

Mr Cummings said the PM would have known if a party was being held by staff in Downing Street despite allies insisting the he could not be expected to know what was happening in every room.

Conservative chief whip Mark Spencer insisted Downing Street staff “were not drinking alcohol” and partying during Covid restrictions after it emerged the Prime Minister’s press chief addressed staff at one event last Christmas.

Downing Street said Mr Johnson retained confidence in communications director Jack Doyle after ITV reported he addressed up to 50 people and made a speech at the party on December 18.

Mr Doyle was also under scrutiny over his attendance at the event on December 11, during which the PA news agency understands he did present awards to the press team.

Asked if Mr Doyle had offered his resignation, the Prime Minister’s official spokesman said: “Not that I’m aware of.”

Mr Cummings said on Twitter Mr Doyle was a “gonner” (sic) but predicted Mr Johnson would keep him on staff until after the Cabinet Secretary’s inquiry, then use him “as the sacrifice”.

Cummings, who left Downing Street in November 2020, said there was no way that Mr Johnson would not have known.

Answering questions on his paid-for blog on Friday, Mr Cummings said: “He knew but I think did not attend.”

But he said: “Tho remember the geography - to get upstairs he has to walk past that area where he could see it - if he was not Chequers...”

It is not clear which alleged gathering Mr Cummings was referring to.