Andrew Mitchell claimed he was the victim of a deliberate attempt to "toxify" the Tories and ruin his career amid mounting pressure on the police over the "plebgate" row.

The former chief whip was forced to quit his Cabinet post amid a storm of protest - fuelled by the Police Federation - over claims he called officers "plebs" during an altercation in Downing Street.

But last week Scotland Yard opened an investigation into a possible conspiracy against the MP after it emerged an email from a civilian witness backing up the claims was in fact written by another officer.

Met Police Commissioner Bernard Hogan-Howe has broken off from his holiday to be briefed on the progress of the investigation which is being supervised by the Independent Police Complaints Commission.

A spokesman said the UK's most senior policeman, who has come under fire for publicly backing the accuracy of the original account of the incident, had an "open mind" and wanted to leave "no stone unturned".

Mitchell spoke out in the Sunday Telegraph as he intensified efforts to clear his name and pave the way for a return to the Government's ranks two months after being forced out.

"These awful toxic phrases which were hung round my neck for weeks and weeks in a sustained attempt to toxify the Conservative Party and destroy my career were completely and totally untrue," he said.

And he expressed incredulity at the latest developments in the case, which have led to the arrest of one officer from the diplomatic protection squad and another man from outside the force.

"If you had told me on 19 September (the day of the altercation) that the events revealed last week could take place in Britain today, I simply would not have believed you."

The Police Federation, which represents rank-and-file officers, yesterday said it planned an independent review into "issues" with its operations.

Local branches organised protests by members wearing "PC Pleb" T-shirts and demanding Mitchell's sacking as it sought to fight off government reforms.

Outgoing chairman Paul McKeever has acknowledged concerns it "stoked up" the original incident and his successor Steve Williams said one of his first acts would be to set up the review.

"Recent events have shown that there are issues around the way the Police Federation nationally is able to lead and co-ordinate at a national, regional and local level," he said in a statement.

Former Met commissioner Sir Paul Stevenson used an article in The Sunday Telegraph to compare elements of Federation tactics with those of "militant trade unionists".

Downing Street meanwhile insisted Prime Minister David Cameron "stood behind" his Cabinet colleague for as long as he could amid criticism from some allies of Mr Mitchell.

Number 10 issued a statement after newspapers quoted members of the Mitchell camp claiming he had been left "swinging in the wind" by the premier who they say failed to act on CCTV evidence that cast doubt on the police account.

"The Prime Minister has deep sympathy for Andrew Mitchell after allegations emerged that a serving police officer fabricated evidence against him," it said.

"The Prime Minister stood behind his Chief Whip through weeks of growing demands to sack him. It was only when it became clear that he could no longer do his job that his resignation was accepted with reluctance.

"Andrew Mitchell did not disagree with the Prime Minister's approach throughout this period.

"The Prime Minister, and Andrew Mitchell, were deeply shocked to be informed that the police were investigating allegations that a serving police officer had lied about the events."

On Thursday, police arrested and questioned a 23-year-old man, who is not a police officer or member of police staff, on suspicion of intentionally encouraging or assisting the commission of an indictable offence on December 14.

That date was a day before a member of the diplomatic protection group was arrested on suspicion of misconduct in public office related to an email sent to his local MP, John Randall, the deputy chief whip.

The email largely backed up the account of what happened in the official log - which was subsequently leaked to a national newspaper.

However the CCTV footage, which Mr Mitchell only saw after he was forced to resign and was broadcast by Channel 4 this week, appears to contradict some elements of those accounts.

Hogan-Howe said subsequent to the arrests that he had seen nothing that "really affected the original account of the officers at the scene".

He will be grilled on the case when he appears before MPs on the Commons home affairs committee next month in a pre-scheduled hearing.

Scotland Yard said: "The Commissioner has broken off from his holiday for a short period because of his concern for the welfare of all the officers and their families involved in the events surrounding the Downing Street incident.

He will also take the opportunity to be briefed on any developments with the investigation, which the MPS is progressing with urgency, whilst maintaining an open mind and a determination to leave no stone unturned."

Tory former policing minister Nick Herbert called for action to tackle what he described as a "cancer" of corruption within the police.

"The truth is that while corruption may not be endemic, neither is it an aberration," he wrote in The Observer.

"The quiet professionalism that ensured the jubilee and the Olympics were kept safe advertised British policing at its best. The Hillsborough report and the weak phone-hacking investigation have shown the service at its worst.

"The extent of wrongdoing should not be exaggerated, but the cancer must be cut out before it spreads. The police do difficult and sometimes dangerous work. They deserve our respect for that and both sides must act to keep it."

He went on: "The sensible majority need to understand how badly they are being let down by a hot-headed minority who have gone too far."

Officers who were censured should be named and shamed to "prevent them obtaining inappropriate employment elsewhere" he said - complaining that more than 200 a year resigned or retired to avoid misconduct proceedings.

And he said the new elected police and crime commissioners should examine how much of their budgets was being spent on Federation officials "agitating politically and often inappropriately".