The exact nature and extent of General Augusto Pinochet's health problems have not been disclosed but along with reports of minor strokes and diabetes, it has been suggested the former Chilean leader could be suffering from dementia.

On 12 January, the UK Secretary of State, Jack Straw, said he was "minded" to block Spain's extradition requests on compassionate grounds, after studying a report from an independent team of doctors who examined Chile's former military ruler.

Mr Straw said it was the "unequivocal and unanimous conclusion" of the team that the general was unfit to stand trial.

Although he did not specifically say it, Mr Straw suggested General Pinochet was mentally unfit to follow court proceedings.

Mr Straw told parliament that in making his decision, he had considered "whether Senator Pinochet would be in a position to follow the proceedings, whether he could give intelligible instructions to those representing him, and whether he could give a coherent statement".

The 84-year-old is said to suffer from diabetes, depression and the effects of two minor strokes last autumn.

Diagnosing dementia

But Amnesty International and a number of other human rights groups are challenging the conclusions of the team who conducted the 5 January medical examination.

They have given the Home Office documents, which include letters from medical experts specialising in Old Age Psychiatry, suggesting the test was insufficient to diagnose dementia.

"Dementia is a big diagnosis. It's a chronic, irreversible condition, and you need to examine the patient at two points in time, or at least have reliable witness accounts that his condition has been like that at two points," Dr Robert Howard of the Institute of Psychiatry at the Maudsley Hospital in London, said.

Cerebro-vascular problems

Both he and Dr Nori Graham from the Royal Free Hospital in London say that in order to diagnose dementia, tests need to be carried out over a minimum of several weeks, outside a hospital environment to "avoid the possibility of corruption the tests by drugs, coaching, sleep depravation and other methods."

Warning the government of the difficulties involved in diagnosing dementia, the human rights groups reminded the Home Office of the case of Guinness-boss Ernest Saunders, who was let out of prison early after being diagnosed with pre-senile dementia. He later made a full recovery and is now an Internet consultant.

The general, however, is reported to be suffering from a number of disabilities. Doctors who examined him are reported to have suggested late-onset diabetes as a possible underlying cause for his cerebro-vascular problems.

'Serious medical conditions'

It is thought the physical and mental symptoms brought on by damage caused by strokes have been compounded by severe depression, which is a common in stroke victims.

Diabetic men are also twice as likely to develop chronic heart disease or strokes, and four times more likely to have poor circulation to their legs. Three-quarters of all patients who are diabetic die of cardiovascular disease.

General Pinochet reportedly visited hospital last August for loss of feeling in his feet.

Supporters of Pinochet, the Chilean government and his own family have said the general's condition deteriorated since his arrest in the UK in October 1988.

General Pinochet came to the UK that year for an operation to treat a spinal hernia. A week after the operation, he was arrested in his hospital bed.

He was reported to have had a number of medical check-ups throughout 1999.

In August, the general's son, Marco Antonio Pinochet, told the BBC that his father was not able to walk and was afraid he was going to lose his legs, citing medical reports which detailed a litany of illnesses.

General Pinochet had just been examined by his own doctor, who found "serious medical conditions, with a significant risk of death". The report detailed 12 illness, including prostate problems, arthritis of the left knee and mild asthma.

A month later, he was reported to have had his first stroke. A brain scan was also carried out.

In October, Bow Street Magistrates court excused the former dictator from attending court while extradition proceedings against him proceeded.