In a letter the Independent Police Complaints Commission accuses the police of changing the findings of an investigation into the conduct of police officers during the "plebgate" row.

Please wait while this video loads. If it doesn't load after a few seconds you may need to have Adobe Flash installed.

The Independent Police Complaints Commission (IPCC) on Tuesday said Inspector Ken MacKaill, Detective Sergeant Stuart Hinton and Sergeant Chris Jones should have faced misconduct hearings for lying about what Mr Mitchell said in a private meeting about the so-called "plebgate" affair last year.

On Wednesday, IPCC Deputy Chair Deborah Glass said in a letter that the final report of the investigation had been substantially altered from the first draft submitted to the IPCC in July.

In the draft version the senior investigating officer concluded there was a "case to answer", says Ms Glass, yet the final report, submitted in August, said there was not.

The conduct of these officers was not acceptable David Cameron

Speaking at prime minister's questions on Wednesday, David Cameron said that at that meeting, Andrew Mitchell had given "a full account of what had happened [during an encounter between Mr Mitchell and police officers in Downing St]", and that "[the police officers] left that meeting and claimed he had given them no account at all. Fortunately this meeting was recorded, and so he's been able to prove that what he said was true and what the police officers said was untrue".

Home Affairs Correspondent Simon Israel writes:

So the plot thickens. Dynamite in a letter from IPCC deputy chair Deborah Glass today that makes the plebgate affair even murkier. She felt the need to respond amid the uproar following a decision to take no action against three officers from the West Midlands Police Federation branch. It turns out that's only half the story.

In a letter obtained by Channel 4 News, sent to three police chief of West Mercia, Warwickshire and West Midlands and the three police and crime commisioners for those forces, Ms Glass reveals why she felt the need to go public in protesting at the decision not put the three officers through a misconduct process for their actions against Andrew Mitchell.

While she accepts the investigation itself was not flawed she writes: "I note that in the first draft submitted to the IPCC in July, the senior investigating officer did in fact conclude there was a case to answer for misconduct, although their final report, submitted in August did not."

Who changed it and why we don't know. Was it pressure from the Police Federation, senior officers or the PCCs?

The prime minister said that "the conduct of these officers was not acceptable", adding "these things should be properly investigated as the home secretary has said", and he backed the decision of the home affairs select committee to call the chief constables concerned to give evidence about the issue.

'Quite wrong'

On Tuesday Home Secretary Theresa May insisted West Mercia police had been "quite wrong" not to take disciplinary action. Mr Cameron said in the Commons that he "agreed 100 per cent with what the home secretary said yesterday".

The force's chief constable, David Shaw, has been summoned to give evidence to the home affairs select committee on the issue. But West Mercia defended its handling in a joint statement with Warwickshire and West Midlands police.

"Andrew Mitchell MP has never made a complaint to police. West Mercia, with the support of West Midlands and Warwickshire Police, recognising the public interest in this case, independently decided to investigate this incident and made a referral to the Independent Police Complaints Commission," the statement said.

Read more: IPCC questions police officers' honesty in 'plebgate' row

"We asked for the matter to be independently investigated by the IPCC because we recognise the significant public interest in the matter, however this was declined.

"The IPCC have supervised this investigation throughout and have been invited to reconsider their position on more than one occasion.

"The decisions following this investigation were carefully considered, with the support of appropriate legal advice.

"Warwickshire, West Mercia and West Midlands Police have separately considered the findings of the investigation and all three forces agree on the outcome."

'Frankly surprised'

West Mercia police Commissioner Bill Longmore expressed surprise about comments by Deborah Glass and said he was seeking an urgent meeting with Mrs May.

"Given the critical statement which the IPCC Deputy Chair has made in the last few hours, I am frankly surprised the IPCC did not resume conduct of the investigation - they certainly had the power to do so," he said.

The chairman of the Police Federation, Steven Williams, also questioned the intervention by Ms Glass.

"My concern is that by releasing her personal view that she disagrees with the findings of the West Mercia investigation she displays a lack of independence," he wrote in a letter to Mrs May.

"This threatens to undermine the considered findings of the investigation in the eyes of the public, whereas in fact those investigating and deciding the case are the proper arbiters in this matter."

'Clear the air'

Mr Mitchell met Mr MacKaill, Mr Hinton and Mr Jones, federation representatives of West Mercia, Warwickshire and the West Midlands respectively, on 12 October to "clear the air".

A transcript shows Mr Mitchell apologised for swearing at the police officers but denied using the word "plebs".

In comments made after the meeting, Mr MacKaill claimed the former Tory chief whip would not provide an account of the incident.

West Mercia police conducted an internal investigation into claims the three officers were trying to discredit Mr Mitchell but concluded there was no case to answer for misconduct or gross misconduct.

However, Ms Glass said she disagreed with their findings and added that the evidence reveals "an issue of honesty and integrity, not merely naive or poor professional judgment" among the federation representatives.

She said: "In the media and political climate of the day, I do not consider that the officers could have been in any doubt about the impact of their public statements on the pressure being brought on Mr Mitchell.

"As police officers, they had a responsibility to present a fair and accurate picture.

'Anti-cuts campaign'

"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."

Ms Glass said the officers must have known Mr Mitchell was under pressure to resign his post following scenes at the Conservative party conference at which federation members were seen wearing "PC Pleb" T-shirts.

In a statement released after the IPCC published its findings, Mr Mitchell said he and his family had "waited in vain" for Mr MacKaill, Mr Hinton and Mr Jones to be held to account.

"It is a matter of deep concern that the police forces employing these officers have concluded that their conduct has not brought the police service into disrepute," he said.

"Most people will disagree. 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.

"My family and I have waited nearly a year for these police officers to be held to account and for an apology from the Police Forces involved. It seems we have waited in vain."

The original incident, in which Mr Mitchell was accused of calling officers guarding Downing Street "plebs" as he cycled through the main gates on 19 September 2012, was the subject of a separate Metropolitan police investigation following claims officers conspired against the politician.

Giving evidence to MPs, 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."

She added: "The police need the trust of the public. These sorts of incident will strike at the heart of that issue of trust."

Operation Alice

Labour former home secretary Jack Straw, who is a close friend of Mr Mitchell, said: "It is lamentable but undoubtedly true, as the IPCC has concluded, that Mr Mitchell has been the victim of wholly unacceptable behaviour by some police officers, a wrong compounded by the woeful inadequacy of the police investigation into this misconduct.

"I hope that this will at last lead to effective action by the employing police forces concerned, and to Mr Mitchell being able to resume his full contribution to British political life. I also hope that the officers concerned might be big enough to apologise."

The Crown Prosecution Service is considering whether to bring criminal charges following Scotland Yard's £230,000-plus investigation, known as Operation Alice. Eight people, including five police officers arrested under Operation Alice, were re-bailed.

The police have come under fire for their handling of the inquiry, with ex-director of public prosecutions Lord Macdonald and Mr Straw among senior figures who criticised the length of time and cost of the inquiry.

Please wait while this video loads. If it doesn't load after a few seconds you may need to have Adobe Flash installed.

Recommended Reading