In questioning the "honesty and integrity" of three police officers who met the Conservative MP Andrew Mitchell over the "plebgate" row - the Independent Police Complaints Commission (IPCC) has dramatically raised the stakes in this stand-off between the politicians and the police.
The meeting happened in Andrew Mitchell's constituency at a time when the former Cabinet Minister was facing accusations that he called police at the gates of Downing Street "f---ing plebs" and "f---ing morons".
He later resigned from his position as Tory chief whip - despite continuing to deny the allegations.
Mr Mitchell met three Police Federation representatives on 12th October last year but the officers have since faced claims they lied about what they were told in that meeting.
The Deputy Chair of the IPCC, Deborah Glass, today concluded that she disagreed with the findings of an investigation by West Mercia Police - which found the officers had no case to answer for misconduct.
The allegation against the officers is that they deliberately misrepresented what Mr Mitchell had said during a meeting in his constituency office on 12 October 2012 when they gave media interviews immediately afterwards.
She added: "Their motive seems plain: they were running a successful, high profile, anti-cuts campaign and the account that he provided to them did not fit with their agenda."
And concluded: "In my opinion the evidence indicates an issue of honesty and integrity, not merely naïve or poor professional judgment."
In response Andrew Mitchell said:
It is a decision which will undermine confidence in the ability of the police to investigate misconduct when the reputation of the police service as a whole is at stake.
The Home Secretary Theresa May has also added her voice the controversy. She told the Home Affairs Select Committee this afternoon that it was "quite wrong" of West Mercia Police not to take disciplinary proceedings against the three officers.
Mrs May said: "The IPCC statement makes troubling reading. If it is indeed the case that warranted police officers behaved in the way Deborah Glass has described, that's not acceptable at all."
Asked if the chief constable of West Mercia Police should apologise to Mr Mitchell, Mrs May said: "I think that would be appropriate."
The criminal inquiry into the original altercation at the gates of Downing Street remains with the Crown Prosecution Service (CPS).
Andrew Mitchell admits he told police that "you lot were supposed to be f---ing helping us" but he claims police officers later falsified their notes.
The CPS is having to decide whether there is enough evidence to push for criminal proceedings against the Metropolitan Police officers involved.
Five serving police officers are among the eight people who have been arrested under the investigation known as "Operation Alice".