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.
Procedural irregularities in @wmerciapolice's Police Fed/Andrew Mitchell investigation means we'll now independently investigate the matter
Keith Vaz, the Chair of the Home Affairs Select Committee says,
"We were appalled by the evidence given by DS Hinton, Sgt Jones and Inspector MacKaill. It is now clear that DS Hinton and Sgt Jones misled the Committee, possibly deliberately. We have recalled them to correct the record and if they do not, they will be in prima facie contempt of Parliament.
"We are also concerned that the chief constables of Warwickshire and West Midlands have not re-determined their conclusions to this investigation.
"We have referred the police officers to the IPCC and we welcome their announcement to make a fully independent decision on this investigation which is what we asked them to consider."
Three Midlands' police officers accused of giving a misleading account of a meeting with Sutton Coldfield MP Andrew Mitchell at the height of the 'Plebgate' affair are facing another investigation by the police watchdog, the IPCC.
Two of the officers will reappear in front of MPs.
They met with Mr Mitchell in their role as Police Federation representatives after the MP was accused of swearing at officers at the Downing Street gates and calling them 'plebs'.
After the meeting the officers claimed Mr Mitchell had not given a full account of the affair.
A tape recording later revealed his level of frankness.
A disagreement has since broken out over whether Inspector Ken MacKaill, Detective Sergeant Stuart Hinton and Sergeant Chris Jones should face disciplinary proceedings.
The Independent Police Complaints Commission (IPCC) will hold its own investigation into their behaviour after finding 'procedural irregularities' in the way the inquiry was dealt with.
Warwickshire Chief Constable Andy Parker has said he was "embarrassed" that his officers had become involved in a heated anti-cuts campaign in the wake of the Plebgate incident.
"My officers got involved in a political campaign which was ill thought-through and has led to a lot of public confidence issues for us," he said.
"I would certainly like to apologise to Mr Mitchell because this added to the already big impact of the Plebgate campaign and it is embarrassing that my force was involved in the way it was."
The chief constable of West Mercia Police has apologised for the findings of an investigation that initially found three Police Federation officers who met Andrew Mitchell had no case to answer for misconduct.
Chief Constable David Shaw has overturned the earlier finding and written a personal letter of apology to the former Chief Whip.
He has asked for another chief constable to be called in to review the decision not to take action against the three officers.
He told the Home Affairs select committee: "Clearly the buck stops with me and I have to be accountable for a huge range of things that go on.
"It's unedifying and it hurts the force."
Chief Constable David Shaw of West Mercia Police has written to former Chief Whip Andrew Mitchell to offer "a profound unreserved apology" over the 'Plebgate' meeting.
He told MPs from the home affairs select committee, he wrote a letter on Monday which was "a personal apology from me".
"It was a profound unreserved apology for the impact what has happened has had on him", he added.
– Detective Sergeant Stuart Hinton from Warwickshire Police
We showed poor judgment in speaking to the media immediately following the meeting with Mr Mitchell. I think we are all happy to take the criticism on the chin for that.
What we should have done is given ourselves an opportunity to debrief the meeting.
We certainly didn't lie intentionally.
Referring to the findings of West Mercia police investigation into a meeting in the wake of the "Plebgate" scandal between three Police Federation officer and former Chief Whip Andrew Mitchell, Michael Ellis MP posed the question "are we dealing with a whitewash here?"
Deborah Glass, Deputy Chair of The Independent Police Complaints Commission, said: "There was certainly. I thought the conclusions were wrong".
The chairwoman and deputy of the Independent Police Complaints Commission are appearing in front of MPs to answer questions over their report into the meeting between Police Federation officers who met former Chief Whip Andrew Mitchell after the 'plebgate' affair.
They questioned the "integrity" of the officers over giving a false account and have said the officers who met Mr Mitchell should have been facing charges of gross misconduct.
The head of Professional Standards, Warwickshire and West Mercia Police has told MPs he thought three Police Federation officers had a case to answer in regards to their actions after meeting Andrew Mitchell after the 'plebgate' affair and didn't agree when "my superiors concluded otherwise".
Chief Inspector Jerry Reakes-Williams, He said that looking at a transcript of meeting and what the officers said there is not "clear case of lying...there is room for doubt".
Mr Reakes-Williams added: "I think the result was that the public were misled but I do not think it was a deliberate attempt to mislead."