An officer is charged over the "plebgate" affair but the CPS finds no evidence the former chief whip was a "victim of conspiracy".
A police officer has been charged with misconduct over the incident at Downing Street with former chief whip Andrew Mitchell.
PC Keith Wallis, a member of the Metropolitan Police Diplomatic Protection Group, has been charged with misconduct in a public office over the "plebgate affair", the Crown Prosecution Service has said.
The officer 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 and then arranged for his nephew to support his false claims.
Mr Mitchell became embroiled in a heated row with an armed police officer on September 19 last year when he was refused permission to cycle through the main gate.
In a statement Alison Saunders, Director of Public Prosecutions, 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.
"With insufficient evidence to show that the officer at the gate lied in his account, we must consider other matters, as set out below, on that basis.
"I have, however, authorised one officer to be charged with one count of misconduct in public office."
There were 10 officers being considered for charges in the wake of the scandal.
The allegations made by Mr Mitchell have led to an extensive police investigation in which hundreds of witness statements from police and Downing Street staff have been taken, the CPS said.
During the incident, which prompted the resignation of Mr Mitchell as chief whip, the officer at the gate claimed that Mr Mitchell shouted at him: "You should know your f***ing place, you don't run this f***ing government, you're f***ing plebs," the CPS statement says.
However, Mr Mitchell claimed he said: "I thought you guys were supposed to f***ing help us."
Crucially the CPS says there is not enough evidence to support the claim that the officer lied about Mr Mitchell using the word "pleb" - a term the MP has always denied using and the word deemed to have cause the political fallout.
The CPS report pointed out that "Mr Mitchell's account has varied since the incident."
A Police Federation statement following the CPS announcement said: "We note the charge announced today by the Crown Prosecution Service (CPS) and await the outcome of the matter once the full criminal justice process has been completed.
"We welcome the decision by the CPS that there was insufficient evidence to show that the officer at the gate lied in his account and that there was insufficient evidence to show that Mr Mitchell was the victim of a conspiracy of misinformation.
"We have always been concerned by the selected information that has been put into the public domain and it is noteworthy that the CPS came to its conclusions after reviewing all the evidence, including unedited CCTV footage from Downing Street."