Mental health campaigners have demanded an overhaul of NHS dementia care after an elderly Alzheimer's patient wandered from a hospital psychiatric ward and died of hypothermia.

Mental health campaigners have demanded an overhaul of NHS dementia care after an elderly Alzheimer's patient wandered from a hospital psychiatric ward and died of hypothermia.

The body of Percy Treble, 81, was found on Boxing Day on an industrial estate 37 hours after he had gone missing from the William Harvey Hospital in Ashford, Kent.

He had been admitted to a "close surveillance" mental health ward for a routine assessment on 23 December but went missing shortly before 9pm on Christmas Eve, sparking a massive police search.

The NHS executive for the South-east yesterday ordered an urgent review by health and social services managers of care at the hospital. Mr Treble's widow called for an independent inquiry.

The East Kent Hospitals NHS Trust confirmed that Mr Treble had been able to leave his bed and dress himself before leaving the unit unnoticed by nursing staff.

Patient groups said the Ashford case was the ninth in two years where elderly patients suffering from dementia had gone missing from wards. The Alzheimer's Society yesterday criticised provision for dementia sufferers, both in specialist units and in general wards where stretched NHS staff often have insufficient information or training to cope.

Harry Cayton, the charity's chief executive, said: "This is a terrible tragedy, and sadly it is not the first hospital where such a case has happened. My fear is it will also not be the last.

"Patients and their families ought to be able to have confidence that a psychiatric ward is safe and that staff are trained to be aware of issues such as confused dementia sufferers trying to leave. Sufferers are admitted both to general wards and psychiatric units, and yet we are seeing that staff are not being given the necessary information. Both guidelines and training must be improved," Mr Cayton said.

Mr Treble, of St Mary's Bay, near Folkestone, had been diagnosed with severe Alzheimer's and was undergoing a care assessment when he arrived at the William Harvey amid concern his condition was worsening. The hospital said yesterday he had been missing for only 10 to 15 minutes before staff alerted Kent Police at 9pm on 24 December.

Wearing trousers and shirt and carrying a pair of slippers, the pensioner walked for two miles across a busy road junction and towards the nearby Sevington industrial park. The retired civil servant's body was found by police on wasteland on the estate shortly before 1pm on December 26. A post-mortem examination found he died of hypothermia.

A spokesman for the hospital said: "Mr Treble was admitted to a psychiatric ward. Patients there are kept under close surveillance, but these wards are not secure and patients have the right to leave.

"An urgent investigation has been launched into... how Mr Treble was able to leave unnoticed. We extend our sincerest condolences to his family," the spokesman said.

Mrs Treble said: "I cannot believe that this has been allowed to happen, especially at this time of year and in this way. I am devastated. My husband's condition was known when he was admitted to that hospital and I feel very strongly that he should not have been put on a ward where he could so easily walk off without being noticed."

The couple's MP, Michael Howard, said an independent inquiry was necessary. The Folkestone MP said: "This is a tragic and unnecessary death. It should not happen, and I believe we should do everything we can to make sure it doesn't happen again."

Campaigners are calling for a voluntary tagging scheme for dementia sufferers, being tested at a Newcastle hospital, to be adopted nationwide.

Health executives at the East Kent Hospitals NHS Trust said the results of their own inquiry into Mr Treble's death would be presented to the Kent Health Authority by the end of this week. An inquest will be carried out at a date to be fixed.

Also last week, an Alzheimer's sufferer was found dead in a storeroom at a hospital in Ireland. He had gonemissing from a secure ward three days earlier.