The police officer at the centre of the Plebgate row has filed a legal claim for up to £200,000 in damages from MP Andrew Mitchell.
Meanwhile, Mitchell is himself continuing to sue The Sun newspaper for libel over its report of the altercation between the former chief whip and PC Toby Rowland outside the gates of Downing Street on 19 September 2012.
It is believed that only Mitchell and Rowland know the truth of the matter.
A High Court claim form, seen by the Mail on Sunday, shows that Rowland is suing Mitchell for slander and seeking an injunction preventing him from repeating the allegation.
Mitchell has admitted swearing at police officers but denies using the phrases “fucking pleb” and “best you learn your fucking place”.
In a press conference in November 2013 he alleged that PC Rowland had invented the phrases which appeared in the police log.
Rowland says he wrote down the comments in his notebook 90 minutes after the event and then emailed his account to senior officers.
Meanwhile, The Sun is running a responsible journalism defence to Mitchell’s claim over its front-page account of the incident.
For its defence to succeed, The Sun does not have to prove that Mitchell said the words – merely that it acted responsibly in reporting on a matter of public interest.
In a comment to the Mail on Sunday, Mitchell (pictured above: Reuters) paid tribute to the role journalists have played shedding light on his story.
A Channel 4 Dispatches investigation revealed last year how a police officer had lied about witnessing the Plebgate incident.
Mitchell said: “Thanks to good investigative journalism much of the truth has already come out.
“There are ten police officers facing some form of misconduct inquiries for what they did and one has gone to jail, with three gross misconduct hearings taking place in London, starting tomorrow [today, Monday – 28 April]. My legal defence to these allegations will begin shortly.”