The police officer at the centre of the "plebgate" row is seeking damages from former Chief Whip Andrew Mitchell of up to £200,000.
PC Toby Rowland is suing Mr Mitchell for suggesting the officer was not telling the truth about the dispute at the gates of Downing Street in 2012.
Mr Mitchell was accused of swearing at police and calling them 'plebs'.
The Conservative MP denies the allegations but resigned as chief whip in the wake of the controversy.
High Court documents show that lawyers for PC Rowland justify the claim on the grounds that his reputation has been damaged by Mr Mitchell's remarks and he suffered "great distress, humiliation and upset".
Conservative MP David Davis, the former shadow home secretary, said it is clear that former chief whip Andrew Mitchell has suffered an injustice an "all that remains is for him to go back into Cabinet."
Mr Mitchell said in a victim impact statement: "The existence of the emails contributed to my acute demoralisation and sense of isolation. They were therefore a contributory factor in the events which led to my resignation."
She added: "The actions of Pc Wallis - and the other officers responsible for turning a largely inaudible altercation lasting less than a minute into a national scandal - have not only caused injustice to Mr Mitchell, they have brought shame upon the police service.
"Now that the criminal proceedings have concluded it is important for the Metropolitan Police Service to proceed as quickly as possible to the misconduct hearings and to deal effectively with any underlying issues so that they can finally close the book on this sorry chapter."
Britain's most senior police officer, speaking after the sentencing of Pc Keith Wallis, said that the officer - who is one year away from retirement - would now be the subject of a misconduct process "as soon as possible".
Pc Wallis's actions have clearly fallen way below the standards that me, my fellow police officers and the public demand.
I expect my officers to serve the public without fear or favour. Where officers break the law they must expect to be held to account and answer for what they have done.
Yesterday I apologised personally to Mr Mitchell that an MPS officer clearly lied about seeing him behaving in a certain manner.
Today, I apologise to the public for Pc Wallis's behaviour.
– Metropolitan Police Commissioner Sir Bernard Hogan-Howe
Also worth remembering PC Toby Rowland, who made 'pleb' allegation, has been fully vindicated by Met/CPS/IPCC, + he is still suing Mitchell.
A Sun spokesman said: "We stand by our story and will defend Mr Mitchell's claim vigorously".
Mr Mitchell is suing the paper for libel.
In a statement, he said: "I am pleased that justice has been done in a criminal court today....I am looking forward to seeing justice done in the up to 10 other related disciplinary cases involving police officers"
David Cameron said it was "completely unacceptable" for a police officer to falsify their account of an incident after PC Keith Wallis pleaded guilty to misconduct in public office over the "plebgate" affair.
The Prime Minister said: “It is completely unacceptable for a serving police officer to falsify an account of any incident.
"Andrew Mitchell has consistently denied the version of events presented in the email and I welcome the fact that the officer concerned has now pleaded guilty.”