The leading Tory said: "There has been a concerted action within the Police Federation to blacken his name and to advance their political cause.
"The Police Federation's reputation is shot. Three or four coppers could go to prison because of this. This is to the Police Federation what phone hacking was for News International."
Last night, as Bernard Hogan Howe, the Metropolitan Police Commissioner, cut short his holiday to be briefed on the progress of the inquiry, he made clear he was "determined there will be a ruthless search for the truth, no matter where the truth takes us".
Earlier, in a 6000-word newspaper article, Mr Mitchell claimed the federation used "Plebgate" to "toxify" the Conservative Party and destroy his political career.
The Midlands MP is now said to be preparing to sue individuals and media outlets, whom he accuses of deliberately trying to destroy his reputation.
However, if the former Cabinet minister desires the support of public and parliamentary colleagues, he might be disappointed. A recent YouGov poll showed 43% of people still believed he probably did call the officers "plebs" while 34% said they did not believe he did.
One Tory colleague said that while the important thing was to vindicate Mr Mitchell's version of events, he did not feel the former chief whip would return to government. "He won't come back," he said. "He is not very popular. He's a spent force."
Pressure on the federation continued to mount with Nick Herbert, the former Conservative Police Minister, calling for action to tackle a "cancer" of corruption within the police.
He stressed that while most officers were hard-working, honest professionals, the "sensible majority need to understand how badly they are being let down by a hot-headed minority who have gone too far".
Elsewhere, Sir Paul Stevenson, the former Metropolitan Police Commissioner, compared elements of the federation's tactics with those of militant trade unionists.
The federation, which represents 130,000 rank-and-file officers, has said it is planning an independent review into "issues" with its operations.
Recently, local branches organised protests by members wearing "PC Pleb" T-shirts and demanding Mr Mitchell's sacking as it sought to fight off Coalition reforms.
Paul McKeever, the outgoing chairman of the federation, has acknowledged concerns that the original incident was "stoked up" and his successor Steve Williams has made clear one of his first acts will be to set up the review.
The Plebgate incident occurred on September 19, when Mr Mitchell tried to cycle through the main Downing Street gates but was stopped by officers and made to use a side gate. A day later, he was accused of swearing at the officers, calling them plebs and morons. He denies this, but accepts he swore "in exasperation".
An email subsequently emerged that confirmed almost word-for-word the police log, which was subsequently leaked to a newspaper, piling pressure on Mr Mitchell. The email, purportedly from a member of the public standing outside the Downing Street gates, was, in fact, from a police officer who was not even present.
He was named yesterday as Keith Wallis, 52, a member of the diplomatic protection group. He has since been arrested on suspicion of misconduct.
CCTV footage casts doubt on claims Mr Mitchell used the offensive words as he left by the side exit, and that there was a crowd at the gates who witnessed the confrontation.
He resigned as chief whip on October 19 because he had lost the support of Tory MPs.
Some 30 officers from Scotland Yard are now working on the investigation, Operation Alice, looking into the incident.
A second diplomatic protection officer, who is thought to have written the police log of the incident, was named yesterday as Toby Rowland, 42.
In his article, Mr Mitchell insisted he was the victim of a smear campaign by "police elements" and gave a line-by-line account of his exchange with the officers.
Mr Mitchell stressed that he now feels his lifelong confidence in the police has been misplaced, adding: "If this can happen to a senior government minister, then what chance would a youth in Brixton or Handsworth have?"
The unfolding of a drama
Sept 19: Chief Whip Andrew Mitchell allegedly calls Downing Street police officers "plebs".
Sept 20: Story leaked to The Sun. Corroborative email about incident received.
Sept 21: Mitchell denies allegations but apologises for disrespecting police.
Sept 25: Police log leaked to The Daily Telegraph.
Oct 17: Labour leader Ed Miliband brands the chief whip "toast".
Oct 19: Mitchell resigns.
Dec 15: Police officer arrested on suspicion of misconduct.
Dec 18: CCTV footage casts doubt on police log. Emailer alleged to be a policeman.
Dec 19: Man aged 23 arrested.
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