Metropolitan Police Commissioner Bernard Hogan-Howe has broken off from his holiday to be briefed on the progress of the 'plebgate' investigation which is being supervised by the Independent Police Complaints Commission.
A Scotland Yard spokesman said Mr Hogan-Howe - 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".
It comes amid mounting pressure on the police over the incident involving former Chief Whip Andrew Mitchell.
In an interview with the Sunday Times (£) Mr Mitchell has accused the police of trying to destroy his career in a smear campaign and says he was being stitched up.
He has also spoken to the Sunday Telegraph and claims he was the victim of a deliberate attempt to "toxify" the Tories and ruin his career.
A Downing Street spokesman has said David Cameron has "deep sympathy" for former Government Chief Whip Andrew Mitchell after it was alleged evidence had been fabricated against him concerning 'Plebgate'.
The Prime Minister has deep sympathy for Andrew Mitchell after allegations emerged that a serving police officer fabricated evidence against him.
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.
– Number 10 spokesman
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.
The policeman at the centre of the 'Plebgate' row involving former Government Chief Whip Andrew Mitchell has been named by the Mail on Sunday newspaper.
The newspaper claims the officer can be seen on CCTV footage ushering Mitchell out of the Downing Street gates during the alleged 'Plebgate' incident and that he was also the author of the police log that documented the exchanges between the pair.
The Mail on Sunday also names the man who sent a letter of complaint about the incident to an MP.
The newspaper states he is related to a second man - a 23-year-old who is not a member of police staff - who has also been arrested over the affair.
Andrew Mitchell has spoken of the “sustained attempt to toxify the Conservative Party” and his reputation after he was accused of calling police officers “plebs”.
Mr Mitchell has told the Sunday Telegraph: “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. I never said them.
“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 has confirmed that "Plebgate" has played into its decision to review its structure.
I'm told the new chairman, Steve Williams, who begins in a few weeks' time, has been keen to hold this ever since the Andrew Mitchell affair broke back in September.
At that time the MP's local police federations (West Mercia, West Midlands and Warwickshire) called for him to quit as Chief Whip. But the national chairman didn't go that far.
But events over recent days - calling the police reports into question - have persuaded Chair Elect, Steve Williams this review must happen as soon as he's in position.
The Police Federation of England and Wales has announced an independent review of its structure following the row over Andrew Mitchell and the so-called "Plebgate" scandal.
The federation's chair elect, Steve Williams, said an independent panel would be set up to ensure it "delivers on its objectives".
"Recent events have shown that there are issues around the way the Police Federation nationally is able to lead and coordinate at a national, regional and local level", Mr Williams added.
Details of the panel will be announced in early January and its initial findings are expected to be reported by April next year.
The Mayor of London has made clear his confidence in Scotland Yard chief Bernard Hogan- Howe, after former Chief Whip Andrew Mitchell reportedly sought assurances that the Commissioner would not be involved in the 'plebgate' investigation.
Boris Johnson's spokesman said:
The Mayor has absolute confidence in the Commissioner. He has assured the Mayor that he is determined to get to the bottom of this as quickly as possible. The Mayor has every confidence in that assurance.
Both the Prime Minister and the Mayor of London have backed the Metropolitan Police chief after former Chief Whip Andrew Mitchell said he had "no confidence" in Bernard Hogan-Howe.
The Evening Standard quotes a Downing Street spokesperson as saying that, "the Prime Minister has full confidence in the Metropolitan police commissioner and believes the police should be allowed to carry out the investigation."
Boris Johnson's office is also quoted as supporting Mr Hogan-Howe, "The Mayor has absolute confidence in the commissioner."
A Number 10 source has said David Cameron met the former Chief Whip Andrew Mitchell on Monday evening in Downing Street.
Mr Mitchell was said to be "calm and rational" but disturbed by the claims about his incident with Downing Street police officers in September and was determined to get to the bottom of it.
The source added there was a lot of sympathy towards Mr Mitchell among Conservative MPs.