Three police officers are challenging the legality of an investigation into their conduct in the Plebgate affair, it has emerged.
The Police Federation is supporting the officers in their application for judicial review of the probe by the Independent Police Complaints Commission (IPCC).
Federation representatives Inspector Ken MacKaill, Detective Sergeant Stuart Hinton and Sergeant Chris Jones were initially told they would face no action over accounts they gave of a meeting with the then Government chief whip Andrew Mitchell the month after his row with officers in Downing Street, but that decision is now being reconsidered.
Mr Mitchell, who eventually resigned from his post, became involved in a heated confrontation with officers in September 2012 after he was refused permission to cycle through the main gate. He later admitted swearing but denied he called officers "plebs".
The following month, he met with Mr Hinton, Mr Jones and Mr MacKaill in his Sutton Coldfield constituency to clear the air, but a further row was sparked when the officers told journalists that he had refused to reveal what he said in Downing Street, something apparently contradicted by a recording of the meeting.
The Police Federation said papers seeking judicial review were lodged at the High Court on Friday and a decision on whether the application will be granted is awaited.
A spokeswoman said: "Following a request to consider the lawfulness of its decision the IPCC was asked to suspend its investigation and an invitation to the officers to attend for interview. This was declined.
"As a result there was no option but to lodge an application for judicial review, which is the appropriate route to challenge decisions taken by a public authority.
"The three officers have been legally advised that the interviews should not now take place while the High Court is seized of the matter. The IPCC have been fully informed of the intention to apply for judicial review and that an application had been issued."
She added: "It is only right and proper that police officers face investigation where they are suspected of wrongdoing. At the same time, police officers are entitled to understand the process that will hold them to account for their actions as with any disciplinary proceedings and to accept the outcome in good faith.
"We believe that the IPCC's actions are unlawful. In the interest of fairness, the system should be changed if it is judged not to be working, rather than move the goal posts after the event. This is now for the High Court to determine."
She said it was wholly inaccurate to suggest that the three officers had refused to meet with the IPCC.
An IPCC spokeswoman said: "Our position is that our investigation is lawful and it remains ongoing.
"When we appeared before the Home Affairs Committee on November 5 we informed them that, unless further lines of enquiry were identified, we would complete our investigation by Christmas.
"As part of the review of the available evidence the investigator did pursue some additional lines of enquiry and as a result there is a delay in the original timing. All interested persons were advised of a possible delay in late November.
"To date, all three officers have been served with notices advising them they are subject to investigation and their actions, if proven, would amount to gross misconduct. We have also redrafted the terms of reference and enhanced the audio recording of the meeting in order to make a definitive transcription of it.
"All that remains to complete the investigation is for the officers to be interviewed. In late December the three officers were asked to agree dates to attend to be interviewed with the investigator but declined to do so. As a result, under the relevant legislation, the investigator has specified times and dates for these interviews later this month (January).
On Friday, a serving police officer, Pc Keith Wallis, admitted lying about witnessing the row in Downing Street.
He pleaded guilty at the Old Bailey to a charge of misconduct in public office, having been charged after sending an email to Conservative deputy chief whip John Randall, who was his MP, wrongly claiming that he had seen what happened as Mr Mitchell left Downing Street on September 19, 2012.
The guilty plea has led to calls for the former international development secretary and chief whip's return to the Government.