A police officer who lied about witnessing the Plebgate row will be sentenced today.
Pc Keith Wallis faces a possible prison sentence after he admitted a charge of misconduct in public office.
Wallis, 53, of West Drayton, west London, sent an email to Conservative deputy chief whip John Randall, who was his MP, wrongly claiming that he had seen what happened as Andrew 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, who was forced to quit over the debacle, later admitted swearing but denied Pc Rowland's claim that he used the word ''pleb''.
Last month, the Old Bailey heard how Wallis, who is from the Metropolitan Police diplomatic protection group, admitted his offence in a police interview and offered to resign.
Mr Justice Sweeney warned him "all sentencing options remain open to the court" and adjourned for pre-sentence psychiatric reports. Wallis is on conditional bail.
Mr Mitchell welcomed the guilty plea and there were calls for his return to Government.
Prime Minister David Cameron issued a statement saying it was "completely unacceptable" for police to falsify their account of an incident.
Metropolitan Police Commissioner Sir Bernard Hogan-Howe, who apologised in person to Mr Mitchell yesterday, said that Wallis's behaviour fell "way below the standards expected" of his officers.
Following the 50-minute meeting in Mr Mitchell's Commons office, where they agreed on the importance of "drawing a line" under the matter, Mr Mitchell said: "I am grateful to the Metropolitan Police Commissioner for his apology."
Following reports of the Plebgate incident in 2012, Mr Mitchell apologised for being disrespectful to police but denied using the words attributed to him.
But his apology was not enough to prevent members of the Police Federation of England and Wales protesting at the Conservative Party's annual conference in T-shirts bearing the slogan "Pc Pleb and Proud".
After meeting the MP in Sutton Coldfield, the Federation's Inspector Ken MacKaill said he had "no option but to resign", while Labour leader Ed Miliband described him as "toast" in the House of Commons and Mr Cameron himself said his chief whip was wrong to use the words he did.
The unrelenting pressure eventually led Mr Mitchell to offer his resignation on October 19, a month after the initial altercation.