London politics latest news: Boris Johnson may have to resign if he lied to Commons, suggests Dominic Raab

It comes after Dominic Cummings, the former chief adviser to the prime minister, said Mr Johnson lied to Parliament when he said he thought a May 20 drinks party at Downing Street was a “work event”.

On Tuesday, Mr Raab was asked by presenter Sally Nugent on BBC Breakfast: “What I am trying to get you to say is in principle if a Minister lies to Parliament and fails to correct it should they resign?”

Mr Raab replied: “Yes”.

Earlier, Mr Raab admitted the Partygate scandal was politically “toxic” and accepted there was a perception of double standards among the public over the string of parties in Downing Street while Covid restrictions were in place.

He, however, said any suggestion Mr Johnson had lied was “nonsense”.

A No 10 spokesman has rubbished the claims.

“It is untrue that the Prime Minister was warned about the event in advance,” the spokesman said, adding Mr Johnson would be making a further statement when Sue Gray, the senior civil servant investigating partying in Whitehall during lockdown, had completed her inquiry.

The allegations will add to the pressure on Mr Johnson, who is facing calls to resign from some Tory MPs amid widespread voter anger at reports that Covid rules were flouted by No 10.