David Cameron condemned his chief whip over a reported foul-mouthed rant at Downing Street police officers.
Speaking on a visit to Greater Manchester Police headquarters in the wake of the murders of Pcs Fiona Bone and Nicola Hughes, Mr Cameron said Andrew Mitchell's behaviour had been "wrong" and "inappropriate", but stressed he had apologised.
The comments came after police groups and Labour questioned whether Mr Mitchell could hang on to his job after details emerged of the confrontation, which happened a day after the two Manchester officers were killed.
According to The Sun, the MP reacted angrily after being told he was not allowed to cycle out of Downing Street. He apparently branded the officers "plebs" for not letting him use the main gates and said they should "learn your f****** place".
Mr Mitchell, who became chief whip in the reshuffle earlier this month, has denied using some of the reported language but apologised for not treating the police with proper respect.
Asked if he would stand by Mr Mitchell or sack him, Mr Cameron said: "What Andrew Mitchell said and what he did was not appropriate. It was wrong and it is right that he has apologised. He has obviously apologised to me, but more importantly he has apologised thoroughly to the police and that needed to be done.
"Police do an outstanding job across our country. They do a very important job protecting places like Number 10 Downing Street and I am very conscious of the protection they give to me and my family and the work they do for everyone in public life. I am eternally grateful for that and the police should always have our respect and our help and support and that is very, very important."
Mr Mitchell made a personal apology to the officer involved by telephone as he tried to limit the damage from the episode. A Cabinet Office spokesman said the officer had accepted Mr Mitchell's apology. No formal complaint has been filed over the politician's behaviour.
The Police Federation of England and Wales, which represents rank-and-file officers, said it was "hard to fathom how someone who holds the police in such contempt could be allowed to hold a public office".
Paul McKeever, the federation's chairman, said: "Mr Mitchell's half-hearted apology for the comments made whilst leaving Downing Street will do little to build bridges with the police, who feel they have once again been treated with a lack of respect and civility by members of this Government."