Speaking at the inquest, Richard Williams said he had lost his son James, aged 19.

But he added: "If this happens to any other lad, it's a problem and it is such a shame."

"If this could be of help to someone else then his death won't have been in vain."

A coroner's court in Chester heard how James died of acute heart failure due to anorexia or bulimia in June.

His parents said he had been a healthy, bright teenager with everything to live for.

But he had gone downhill after failing to recover properly from a virus when he was 14.

Mr Williams said his family believed he had ME.

Potassium shortage

At the age of 17, he moved out of the family home in Buckley, North Wales, and went to live in Chester.

Almost as soon as he arrived, he was treated for depression and anorexia and was prescribed potassium replacement tablets.

Eating disorders can deprive the body of potassium and severe shortage of the mineral can cause heart failure.

His body was discovered by his mother Enid. She became alarmed when she went to visit him and could not get into his flat, despite hearing music coming from a radio inside.

She called the police who found James in his bedroom.

Mr Williams said his son was "extremely clever", good at rugby, tennis and swimming and "a perfectionist".

He criticised doctors for not telling him how ill his son was and said that, had he known, he would have paid for hospital treatment for him.

Male eating disorders

Around 10% of Britain's estimated 60,000 anorexics and bulimics are male.

Doctors differ as to the causes of the diseases. Some say it is similar to other obsessive disorders; others blame depression; others say sufferers are trying to avoid growing up and some think it is linked to genetic factors or a brain deficiency.

Anorexics starve themselves while bulimics engage in a destructive cycle of starving and binging.

Health problems linked to starvation include heart failure, kidney disorders, infertility and bone deficiency.