Andrew Mitchell has 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".
Mr 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, on Saturday said it planned an independent review into "issues" with its operations. 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.
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."