The commissioner of the Metropolitan Police has apologised to former Cabinet minister Andrew Mitchell after a serving police officer admitted lying about witnessing the row that led to his resignation from the UK Government.

Mitchell welcomed the guilty plea by PC Keith Wallis to a charge of misconduct in public office, saying that “justice has been done” in the case.

The guilty plea at the Old Bailey led to calls for the former international development secretary and chief whip’s return to the Government, which he quit in 2012 after allegations that he had sworn at police and called an officer a “pleb” when he was prevented from cycling out of the gates of Downing Street.

Prime Minister David Cameron welcomed Wallis’s guilty plea, saying that it was “completely unacceptable” for police to falsify their account of any incident.

But there was no mention in his brief statement issued by Number 10 of whether the development will open the door for a return to ministerial office for Mr Mitchell.

Unacceptable for serving police to falsify account of any incident

Wallis, 53, of West Drayton, west London, was charged after sending an e-mail to Conservative deputy chief whip John Randall, who was his MP, wrongly claiming that he had seen what happened as Mr Mitchell left Downing Street on September 19, 2012.

The then chief whip became involved in a heated confrontation with another police officer, Toby Rowland, after he was refused permission to cycle through the main gate.

The Sutton Coldfield MP later admitted swearing but denied PC Rowland’s claim that he used the word “pleb’’.