West Mercia Police have confirmed they are reviewing a report on the 'Plebgate' scandal which is alleged to have been fundamentally altered.
Claims have emerged police officers changed the conclusions of a probe into a meeting between Andrew Mitchell and federation members.
In questioning the 'integrity' of plebgate officers the IPCC has dramatically raised the stakes in standoff between politicians and police.
Chief Inspector Jerry Reakes-Williams, who investigated whether Midlands police officers lied after a meeting with Sutton Coldfield MP Andrew Mitchell, has told MPs he disagreed with his senior colleagues.
– Chief Inspector Jerry Reakes-Williams, Professional Standards, Warwickshire and West Mercia Police
"I thought the three Police Federation men had a case to answer and didn't agree when my superiors concluded otherwise."
The Home Affairs Select Committee are hearing from Chief Constables, the IPCC and the Police Federation later today over 'plebgate', which led to Sutton Coldfield MP, Andrew Mitchell, resigning from his role as government chief whip.
Chief Inspector Jerry Reakes-Williams, who represents professional standards at Warwickshire and West Mercia Police is giving evidence.
He has said that comments made by officers after their meeting with Andrew Mitchell had the effect of misleading the public.
"I do not take the view that the view that they lied deliberately, hence why it was a case of gross misconduct, not misconduct."
CI Reakes-Williams has said that Mr Mitchell is owed an apology and also admitted that the row had damaged the reputation of the forces involved.
Andrew Mitchell has remained tight-lipped over whether he would hope to be vindicated over the 'plebgate' affair as he arrived at an airport in Washington.
MPs on the home affairs select committee are to question three Police Federation officers accused of misrepresenting the former Chief Whip after a meeting over the incident last year.
David Cameron said at Prime Minister's Questions he hopes chief constables and Police Federation officers will give a "full account and a proper apology" when they appear before MPs over the "plebgate" investigation.
Keith Vaz MP says he wants to 'establish the facts' and find out why the IPCC did not agree with the conclusions of other police chief constables after they last looked at the 'plebgate' row.
The Home Affairs Select Committee will hear from Chief Constables, the IPCC and the Police Federation later today over 'plebgate', which led to Sutton Coldfield MP, Andrew Mitchell, resigning from his role as government chief whip.
The plebgate row has clouded the public view of Scotland Yard and has taken too long to deal with, Britain's most senior police officer has admitted.
Speaking to Nick Ferrari on LBC this morning, Metropolitan Police Commissioner Sir Bernard Hogan-Howe said:
"During the time this thing has been an issue, the Met has been performing better than ever. We've just got to live with the reality - the newspaper headlines, the fact that you're talking about it, clouds the fact that crime's coming down at its fastest for 30 years.
"This issue's got to be resolved and we've got to deal with it."
He added: "We're all eager to see the outcome of this inquiry and that we get back to some kind of normality, because I think it's not good for the police and it's not good for public confidence.
I'm determined to get to the bottom of it, we've got a thorough investigation and we really now have to await the outcome of that."
Senior Conservative MP David Davis has called for police officers to wear a camera and microphone while on duty in the wake of the "plebgate" row.
Mr Davis, an ally of Andrew Mitchell and a former shadow home secretary, wrote in The Times (£) that such technology could help curb the use of force by officers and also "help to defend police officers who have vexatious claims made against them".
He said there is "a crisis of ethics" within the service and called for "root-and-branch reform of policing culture", starting with a Government-appointed Royal Commission to investigate their conduct.
"Regrettably it appears that the Mitchell case is merely a high-profile example, not an isolated one", he added.
The Home Affairs Select Committee will hear from Chief Constables, the IPCC and the Police Federation later today over the 'plebgate' row which led to Sutton Coldfield MP, Andrew Mitchell, resigning from his role as government chief whip.
Inspector Ken MacKaill, Detective Sergeant Stuart Hinton and Sergeant Chris Jones were accused of lying about what Andrew Mitchell said in a meeting at his Sutton Coldfield constituency office held nearly a month after the so-called "plebgate" row erupted.
A transcript shows Mr Mitchell apologised for swearing at the police officers but denied using the word "plebs", while in comments made after the meeting Mr MacKaill claimed the former Tory chief whip refused to provide an account of the incident.
The officers, who were representing the forces of West Mercia, Warwickshire and West Midlands, were spared misconduct proceedings by an internal investigation.
But the Independent Police Complaints Commission (IPCC) later disputed the findings and said there were issues of "honesty and integrity" among the three men.
The federation representatives will give evidence to the Home Affairs Select Committee before the chief constables from all three forces - Andy Parker of Warwickshire Police, David Shaw of West Mercia Police and Chris Sims of West Midlands Police - also appear.
Three police officers caught up in the so-called Plebgate row are to be grilled by MPs later.
Police Federation representatives Inspector Ken MacKaill, Detective Sergeant Stuart Hinton and Sergeant Chris Jones were accused of trying to discredit former Tory chief whip Andrew Mitchell after meeting him in October last year.
Mr Mitchell met the three officers after he was accused of calling officers guarding Downing Street "plebs" in a foul-mouthed rant as he was asked to cycle through a side gate on September 19 last year.