A mental hospital in the North-East has been chosen to pilot a way of treating potentially dangerous patients.

The personality disorder unit at St Nicholas' Hospital, in Newcastle, which services the entire region, will be the first dedicated unit of its kind in the North of England.

When it opens in 2005, it will be one of only three specialist treatment units in England, the others will be in London.

It follows widespread concern at the failure to adequately treat patients with personality disorders.

The condition - which affects at least one per cent of the population - is regarded as very difficult to treat.

Until now, few hospitals in the UK have been confident about dealing with patients who often claim they are not mentally ill.

In one case, Michael Stone, a mental patient diagnosed with severe personality disorder went on to murder Lin Russell and her six-year-old daughter, Megan, during a country lane attack near Canterbury, Kent, in 1996, after refusing conventional psychiatric treatment.

While the 16-bed facility in Newcastle will not admit the most dangerous patients, the personality disorder unit will have a medium secure rating.

It will treat patients who have already offended and demonstrated that they may be a risk to the public.

Professor Don Grubin, a consultant psychiatrist at the Newcastle hospital, believes that personality disorder can be treated by a mixture of psychotherapy, counselling and medication.

He welcomed the creation of new units to treat personality disorder - along with separate prison and hospital units for so-called DSPD patients (Dangerous Severe Personality Disorder) - as the first serious attempt to tackle this disorder.

One of the specialist units chosen to pilot ways of treating personality disorder is the high security Frankland Prison, in Durham

Prof Grubin said: "Our aim is to develop treatment expertise. These patients will only be coming here if we feel we can treat them. We are not just going to warehouse them."

He said that the hospital already had a medium secure unit and had treated patients with personality disorders in the past. "We don't need high security, we are not going to take that sort of patient," he said.

A separate community team is also being set up at the Newcastle unit to provide outreach services to patients suffering from personality disorders.