Dominic Cummings’ allegation that Boris Johnson lied to Parliament over claims of rule-breaking parties in Downing Street is “nonsense”, the Deputy Prime Minister has said.

As Mr Johnson faced fresh calls to resign, Dominic Raab insisted the Prime Minister had been “straightforward” with MPs when saying he believed a garden party during lockdown would be a work event.

Former chief adviser Mr Cummings said he was willing to “swear under oath” that Mr Johnson did know in advance about a “bring your own booze” event in the garden of No 10.

He alleged that the Prime Minister “waved it aside” when he warned him about the party scheduled for May 20 2020 and urged him to “grip this madhouse”.

But Mr Raab told Times Radio: “The suggestion that he lied is nonsense. He’s made it very clear to the House of Commons … that he thought it was a work event.”

Appearing on Sky News, Mr Raab said he is “confident he’s been straightforward with” Parliament and said the “PM has been very clear that that’s not true or accurate” when pressed about Mr Cummings’ claims.