A Tooting-based doctor is giving hope to ME sufferers after discovering a potential cause and treatment for the mysterious illness.

Dr Jonathan Kerr, who leads a four-strong research team based at St George's Hospital, believes ME sufferers have white blood cells that behave abnormally when triggered by an outside virus, such as Epstein-Barr.

This leads to symptoms such as weakness, headaches, disrupted sleep and fatigue. (ME is often referred to as chronic fatigue syndrome.)

Many doctors have dismissed ME as a psychological illness, to the despair of sufferers, but Dr Kerr's research could lead to a diagnostic test and treatment.

Dr Kerr said: "We first need to work out how ME is caused and that is what we are doing. We can then use that information for a treatment.

"We have our first experimental drug planned for this year. It is a known drug but we will be using it for a different purpose."

The drug, interferon, is currently used for multiple sclerosis patients.

Dr Kerr will be giving talks in Ireland and London during ME Awareness Week which starts next Sunday, May 7.

Explaining his devotion to the research, Dr Kerr said: "The reason we have taken it up is because ME is an unknown area and research is very badly needed.

"We are disappointed that it has been dismissed as being all in the mind.

"For this reason we are taking it on."

Tony Golding, from Network Mesh, a support group for ME Sufferers in Wandsworth and across London, praised the work of Dr Kerr's team. Mr Golding said: "There is plenty of evidence that there are differences in both the brains and the blood of people with ME. But the question is what to do about it.

"Of course, any research and possible treatment is good. ME is an illness that affects at least 150,000 people in this country."