A police officer was drunk and incensed at the treatment of the police when he sent an email to his MP falsely claiming to have seen the "Plebgate" row, the Old Bailey heard today.
"Rumour and gossip" over the Downing Street incident in which then chief whip Andrew Mitchell was accused of calling an officer a "pleb" angered the serving officer and combined with high emotions over the killing of two female officers in Manchester the day before.
It was in this state that Keith Wallis got drunk after his shift and went home to send the late night email full of spelling mistakes and capital letters to his MP, Conservative deputy chief whip John Randall.
But after sending the email in which he stated he did not believe Mr Mitchell should lose his job, events "got completely out of hand" his lawyer Patrick Gibbs QC said.
Mr Randall's interest in the case in Westminster combined with media involvement escalated the situation and Wallis did not have the mental capacity to come clean and put a stop to it, the court heard.
He was caught out in the lie when CCTV showed he was not at the Downing Street gates with his nephew at the time of the row with Mr Mitchell, as he had claimed.
But Mr Gibbs insisted there was no conspiracy at play, rather Wallis had convinced himself he had witnessed the incident on 19 September 2012.
Mr Gibbs said: "While it is impossible to pinpoint the moment Mr Wallis came to believe that video in his head, he did genuinely come to believe it."
When he was arrested, Wallis, 53, of West Drayton, West London, admitted the lie and offered his resignation, commenting that he should have thrown himself under a train the day before, the court heard.
Last month, the officer from the Metropolitan Police diplomatic protection group pleaded guilty at the Old Bailey to misconduct in a public office.
Mr Gibbs said Wallis, who served for 30 years, suffered from both mental and physical illness and had been deeply affected by the death of his father, who was also a police officer.
Appealing to the judge not to send him to jail, Mr Gibbs said: "He would be the ideal scapegoat for more sophisticated men but sending him to prison would be to mistake this for what it is not."
Mr Justice Sweeney will sentencing later.