A police officer is to be charged with misconduct in public office over the Plebgate row, prosecutors have said.
Pc Keith Wallis is accused of sending an email to the deputy chief whip, John Randall, who was his MP, falsely claiming that he had witnessed the incident in Downing Street last year.
A row erupted after then-chief whip Andrew Mitchell became involved in a heated confrontation with an officer after he was refused permission to cycle through the main gate.
Mr Wallis is due to appear at Westminster Magistrates' Court on December 16.
However, prosecutors have concluded that there is insufficient evidence to bring any charges against the officer at the gate.
Director of Public Prosecutions Alison Saunders said: "We have considered all of the evidence in this case, including previously unseen, unedited CCTV footage from Downing Street, not referred to by the media.
"Taking it all into account, including the accounts of the officer at the gate of Downing Street and that of Andrew Mitchell MP before, during and after the incident, we have found that there is insufficient evidence to show that the officer at the gate lied in his account. The CPS has also found that there is insufficient evidence to show that Mr Mitchell was the victim of a conspiracy of misinformation."
Evidence in the case was reviewed by a specialist prosecutor and Ms Saunders was given advice by a QC.
Prosecutors have decided that there is not enough evidence to prove that any officer made a false allegation against Mr Mitchell, or of any criminal conspiracy.
They found that the leak of the gate officer's email account of what happened, by a colleague unconnected to the incident, to the media, was in the public interest.
Ms Saunders said: "This type of conduct raises issues in relation to the right to freedom of expression, including the right to freely impart and receive information, and these are important rights enshrined in our law.
"In all the circumstances of this case, we have concluded that a jury is likely to decide that it was in the public interest for the events at the gate to be made public and it therefore follows that there is insufficient evidence to prosecute any suspect in relation to this leak."
She said that CCTV evidence and emails and other messages between police and members of the public had been scrutinised.
"The allegations made by Mr Mitchell led to an extensive police investigation involving hundreds of witness statements from police and from staff at Downing Street.
"Previously unseen and unedited CCTV evidence has been considered very carefully. In addition there has been a detailed inquiry into emails, text messages, social messaging and telephone contact between numerous police officers and members of the public.
"The locations of mobile telephones have been analysed using cell site technology. We have considered evidence in relation to 14 individuals, including 10 police officers, a member of the media and three members of the public."
Eight people, including five police constables and three members of the public, were arrested and bailed until this week.
Ms Saunders highlighted the conflicting accounts of what Mr Mitchell said. The gate officer claims he used the words: "You should know your f****** place, you don't run this f****** government, you're f****** plebs."
However Mr Mitchell claimed he said: "I thought you guys were supposed to f******help us".
Ms Saunders said: "We have been supplied with previously unseen and unedited footage of the incident from five different cameras. The CCTV footage does not determine the issue completely as it could be consistent with either the accounts of the officer on the gate or Mr Mitchell.
"It is clear from the footage that there was sufficient time for the words to have been said either as described by the gate officer or as described by Mr Mitchell, and this has been confirmed by an expert. The fact that an expert has confirmed what is possible does not of itself determine the issue.
"Both the officer and Mr Mitchell agree that the officer warned him about swearing and that Mr Mitchell made a further remark on leaving. There is no sound recording and the faces of the officer and Mr Mitchell cannot be seen sufficiently clearly. It does show that there are a small number of members of the public present immediately in front of the gate at the relevant time, but what cannot be seen is how many people were immediately off camera but in the vicinity, at least some of whom then quickly came into view.
"Our determination in relation to the incident also involved careful consideration of evidence concerning conduct and communications by officers and Mr Mitchell both before and after the incident, including the fact that Mr Mitchell's account has varied since the incident."
There was "information but no admissible evidence" suggesting that an officer's partner had contacted the media about the row, adding the word "morons" to the account, but a charge of misconduct in public office cannot be brought because they are a member of the public, the CPS said.
Another unconnected member of the public sent an email to the chairman of the Conservative Party claiming to have witnessed and filmed the incident, and alleging that the word "pleb" was not used, but again prosecutors cannot bring a charge of misconduct in public office.
Charges of perverting the course of justice were also considered against two officers for statements they gave to the investigation, but there was insufficient evidence for a conviction.