The independent police complaints watchdog was today forced defend itself against claims it was overseeing a "rambling" investigation into the damming allegations that serving officers tried to frame a Cabinet Minister.
It is a year today since Andrew Mitchell was first accused of calling police protection officers 'plebs' when they prevented him from cycling through the main gates of Downing Street.
But despite evidence that a police log was inaccurate and that Mr Mitchell never used the words ascribed to him no-one has yet been charged with any offence or disciplined.
Today the former Conservative leader Lord Howard said it seemed "extraordinary" that it should have taken a year to investigate an incident that lasted 45 seconds.
He was backed by the Former Director of Public Prosecutions Lord Macdonald who said it was "outrageous" that the police investigation was still on-going. He accused the Metropolitan Police of acting liked "rabbits blinded in the face of an approaching storm".
"It seems quite outrageous that, in the face of the simplicity of the allegations and this significant commitment of public resources, the investigation rambles on with no apparent end in sight," he wrote.
"We are talking here about the resignation of a British Cabinet minister, a resignation forced upon him at the height of his career by police allegations that are now seriously called into question.
"An expeditious and thorough investigation should have been perfectly possible."
Lord Howard said there would be "very serious consequences" if the police concluded that Mr Mitchell did not use the word 'pleb'.
"There's a great deal at stake," he said. "Let's wait and see what the outcome of the investigation is, but if it turns out that the career-killing use of 'pleb' - that lethal single-syllable exocet - was fabricated, as Mr Mitchell has always claimed, then there's no doubt in my view that the consequences will be very serious."
But responding to the allegations that the inquiry is taking too long the Metropolitan Police said it was complicated and will "take as long as is necessary", while the Independent Police Complaints Commission (IPCC) has said "all that can be done to conclude the investigation is being done".
Deborah Glass, deputy chairwoman of the IPCC, which is supervising two investigations into the incident on September 19 last year, added: "While the incident which sparked this investigation is on the face of it simple - it took less than a minute to unfold - what has evolved are allegations of a conspiracy which by its very nature is complex.
"While I share the concerns of others that the investigation is taking far longer than originally anticipated, I am regularly updated on its progress, I am personally reviewing the evidence and I am satisfied that all that can be done to conclude the investigation is being done and that Mr Mitchell himself is kept informed."
Nine Met officers have been or are being investigated for criminal and misconduct offences as part of the Metropolitan Police investigation, known as Operation Alice, the IPCC said.
Four others who are not police officers have also been or are being investigated.
The so-called plebgate row was ignited when Mr Mitchell was accused of launching a foul-mouthed rant at officers guarding Downing Street as he asked to cycle through the main gates on September 19 last year.
Pressure intensified after the Daily Telegraph published a police log of the incident, which claimed he called officers "plebs" and swore at them repeatedly for making him walk through a side gate.
He insisted he did not use the words attributed to him, and later said he was the victim of a deliberate attempt to "toxify" the Tories and ruin his career.
A Channel 4 investigation cast doubt on the officers' account when it revealed CCTV footage which showed there was not a large group of tourists outside the main gate at the time as had originally been claimed.
An email from a civilian witness backing up the police account of events has also been called into question.
A second investigation was referred by West Mercia Police to the IPCC into an allegation that a West Mercia Police Federation representative gave a false account of a meeting with Mr Mitchell in an attempt to discredit him.
That investigation was later widened to include the federation representatives of the West Midlands and Warwickshire forces, who were also at the meeting.
A spokesman for the Met said: "This investigation is examining very serious allegations that go to the heart of the public's trust in the police service.
"The MPS is conducting a thorough investigation that aims to establish the truth of what has taken place and find the best possible evidence.
"An initial file was passed to the CPS in March 2013, however since that time three separate pieces of information have been given to us. As a result further inquiries have had to be made."