A police officer who claimed in a drunken rage to have witnessed the 'Plebgate' row has been jailed for a year for misconduct in a public office.

PC Keith Wallis, 53, of London, sent an email to Tories' deputy chief whip John Randall, who was his MP, wrongly claiming he had seen what happened as Andrew Mitchell left Downing Street on September 19, 2012.

Mr Mitchell, then chief whip, had been involved in a heated confrontation with another police officer, Toby Rowland, after he was refused permission to cycle through the main gate. It was claimed Mr Mitchell called the officer a "Pleb".

The Old Bailey, London, was told that Wallis, who worked at Metropolitan Police diplomatic protection group, was moved to act by "rumour and gossip" about the incident.

The officer, who was just one year from retirement after a 30-year career, was also intoxicated and suffering from mental illness at the time, the court was told.

Following a month of intense media interest in the story, Mr Mitchell, who always denied using the word "Pleb", was forced to resign his post.

Defending, Patrick Gibbs, QC, appealed for leniency for Wallis, who had admitted the offence.

But Mr Justice Sweeney dismissed his plea, telling Wallis his "devious" actions "fell far below the standards expected of a police officer".

Mr Sweeney said his actions not only had an impact on Mr Mitchell but also had "a significant impact on public trust and confidence in the integrity of police officers".