Andrew Mitchell, the former Tory chief whip, is being sued for libel by the Downing Street police officer at the centre of the “plebgate” row.
The 14-month-old controversy took a fresh twist when PC Toby Rowland announced plans for legal action against Mr Mitchell.
He was on duty when the former Cabinet Minister attempted to cycle through the main Downing Street gates and was told to use a smaller side gate instead.
According to the police log written by PC Rowland, Mr Mitchell said officers were “f**king plebs” and told them to “know your f**king place”.
The MP strongly denies that version of events and insists he said: “I thought you guys were supposed to fucking help us.”
Last week Mr Mitchell accused the officer of not telling the truth and claimed he had been “stitched up” by police over the clash, which led to his resignation from the Government.
He challenged PC Rowland to give evidence on oath about the episode as part of a libel action he was pursuing against The Sun newspaper.
The Police Federation announced the officer had issued a letter of claim for libel against Mr Mitchell over “comments he made following the media-termed plebgate incident”.
Mr Mitchell said last week: “I was fitted up in Downing Street by armed police officers whose sole duty is to defend officials and to defend Downing Street. We believe the CCTV shows the account of Pc Toby Rowland is at very best inaccurate. I never said these phrases.”
But PC Rowland stood by his account and the Police Federation said it was giving him its full backing, including legal advice.
The Tory MP David Davis, a strong supporter of Mr Mitchell, said: “We have been trying to get Pc Toby Rowland into the witness box to face the evidence and cross-examination under oath – and if this law suit by any means accelerates that, so be it.”