A carer who assaulted an elderly woman with dementia was not prosecuted because it was "not in the public interest", a former coalition minister has claimed.
Richard Benyon MP said a constituent of his caught a "brutal assault" on his mother by her carer on CCTV cameras after installing them in her flat.
But the Crown Prosecution Service (CPS) refused to prosecute the carer because it was "not in the public interest", the Tory MP for Newbury said.
Prime Minister David Cameron said he could not comment on the specific case but insisted that it was right to be "intolerant" of breaches of care against elderly people, particularly those with dementia.
During Prime Minister's Questions in the Commons, Mr Benyon said: "My constituent installed CCTV in his mother's flat because she was a dementia sufferer.
"He recorded on this a brutal assault on her by her carer. Unbelievably to me the CPS has refused to prosecute her because they say it is not in the public interest.
"Would you agree with me that as a society we should be totally intolerant of all attacks on vulnerable people with dementia?"
Mr Cameron replied: "On the specific case of course it wouldn't be right for me to comment on a CPS decision.
"But on the general point about is it right that we are intolerant of breaches of care against elderly people, particularly those with dementia who are reliant on others? Yes, we should be intolerant to that.
"Our dementia strategy is all about not just increasing the research into trying to tackle dementia but making sure our care homes and hospitals and indeed communities become more dementia friendly."