Former Cabinet minister Andrew Mitchell must accept the verdict of the High Court on the "Plebgate" libel action and move on, David Cameron has said.

The Prime Minister insisted it was "never right to be abusive or rude" to a police officer and said the judge had "made very clear his verdict".

Mr Justice Mitting decided the former chief whip did call PC Toby Rowland a "pleb" because the officer did not have the "wit, imagination or inclination" to invent it.

Asked about the outcome of the case after he made a speech in Staffordshire on immigration, Mr Cameron said: "Let me be clear - it is never right to be abusive or rude to a police officer. I think that is extremely important.

"But, look, we've had a court case now. That's how we do things in this country.

"The judge has made very clear his verdict and I think everyone should accept that verdict and move on."

Mr Justice Mitting said he reached the "firm conclusion" the 58-year-old MP used the word "pleb" in Downing Street in September 2012 when he was not allowed to cycle through the main vehicle gates.

Mr Mitchell, who resigned as whip a month after the altercation, denied during his two-week libel action against News Group Newspapers (NGN) that he had said: "Best you learn your f****** place - you don't run this f****** government - you're f****** plebs."

He said he would never call a policeman a pleb "let alone a f****** pleb", although he agreed he muttered under his breath "I thought you lot were supposed to f****** help us" - but not directed at the officer.

The Conservative MP, who now faces a hefty legal bill after losing the case, said he was "bitterly disappointed" with the ruling.

A senior police constable who was on duty in Downing Street at the time of the row said he feels sorry for Mr Mitchell.

Ian Richardson, who recently retired after 30 years in the Metropolitan Police, said it was a "nonsense incident" and criticised Scotland Yard's handling of the row.

He said no-one should have lost their job over what happened at the gates of Downing Street and accused the Police Federation.

Mr Richardson, who heard part of the exchange and gave evidence in the High Court case, told the BBC Radio 4 Today programme that the Met should have drawn a line under the incident.

"I said in my evidence in chief last week that it was a nonsense incident that shouldn't have cost Mr Mitchell his job, certainly shouldn't have cost the officers who were whistleblowers or - whatever your opinion of them is, whether they were leakers or whistleblowers - it shouldn't have cost them their jobs."