The plans include two options, the most controversial being a proposal to lock up people deemed a risk to the public even if they have not committed any crime.

They have drawn many different comments from mental health charities. Here, the National Schizophrenia Fellowship outlines its fears that the plans may increase the stigma attached to mentally ill people.

While SANE says specialist help for people with severe personality disorder could reduce the stigma on mentally ill people who pose no risk to others.

Cliff Prior, chief executive, National Schizophrenia Fellowship

"David is the sort of person likely to be caught up in the government's plans. He is only 25 years old, but has spent 10 years spinning through the doors of various psychiatric hospitals before ending up at an NSF outreach project.

"He had a disrupted and difficult childhood, passed through a range of mental health units and was handed conflicting medical diagnoses before being labelled with a severe anti-social personality disorder.

"He has convictions for theft and assault.

"Yet, over the past year, he has succeeded in beginning to put his life back together, tackling the practical problems of accommodation, money and prescribed drug addiction.

"He is in contact with his family once more.

"Such a positive outcome would not be possible if these new plans had been implemented just a short time ago.

"NSF fears that new personality disorder units will become 'dustbins' for people like David. whose illnesses have proved difficult to diagnose or have just been badly treated.

"They will increase stigma by linking, in the public's mind, mental ill health and dangerousness.

"What David - and the general public - needs is investment in early diagnosis and treatment, proper risk assessments and accessible quality services spread across the country.

"That would encourage people like David to engage with the services. The government plans may have just the opposite effect."

Marjorie Wallace, chief executive, SANE

"Whilst we don't believe in long-term detention for a person who has committed no offence, there are a small number of people who, for their own protection and the protection of others, should have specialised management and help which is neither punitive nor uses sorely stretched mental health resources.

"What is shocking is that if a person is deemed 'untreatable', even if they seek help, they are abandoned by the psychiatric services and have to wait until they are picked up by the prison service.

"Yet it is still often chance whether someone is diagnosed as being treatable or untreatable.