The policeman at the centre of the Plebgate row is demanding up to £200,000 in compensation from the MP for Sutton Coldfield Andrew Mitchell.
Toby Rowland has filed court papers repeating his claim that Mr Mitchell used the term "plebs" during their confrontation in Downing Street in 2012.
He also argues that the then chief whip, who was forced to resign in the wake of the controversy, changed his story after effectively admitting in a phone call that he had said the disputed words.
The documents have been lodged as part of a libel battle between the MP, the police officer, and The Sun newspaper.
Stating his case in detail for the first time since the incident, Mr Rowland insists Mr Mitchell erupted after being blocked from cycling out of the pedestrian gate to leave the street.
The politician has previously admitted to using "Anglo-Saxon" language, but said he did not swear at police, and denied using the term "plebs".