On Wednesday, Boris Johnson announced Cabinet Secretary Simon Case will lead an inquiry into an alleged boozy Christmas gathering in Number 10 in December.
Mr Cummings suggested the investigation should also look at parties he claimed had taken place in the Prime Minister’s own Downing Street flat, including one he alleged happened on November 13 when the country was in the grip of a second national lockdown.
He tweeted: “Will the [Cabinet Secretary] also be asked to investigate the *flat* party on Fri 13 Nov, the other flat parties, and the flat’s ‘bubble’ policy.”
During PMQs on Wednesday, Labour MP Catherine West asked whether there was a party in Downing Street on November 13.
Mr Johnson denied the accusation and said: “Mr Speaker, no, but I’m sure that whatever happened the guidance was followed at all times”.
Mr Cummings left his job at No 10 on Friday, November 13, following internal battles over his role as chief adviser and eight days after the Government imposed the country’s second national lockdown.
He has also faced his own allegations of defying lockdown rules when it was revealed he left London for a trip to his family’s home in Durham during the first national lockdown.
However, he insisted his staff had repeatedly assured him “there was no party and that no Covid rules were broken”.