The government is launching an independent medical investigation into the health of 20,000 volunteers involved in biological and chemical weapons trials at its Porton Down defence establishment.

Many volunteers exposed to nerve gas and other chemical and biological agents at the laboratories on Salisbury Plain in Wiltshire say the tests left them with long-term ill health.

There is compelling evidence that some were given highly dangerous doses.

And some say they were tricked into participating in the tests by being told they would be researching the common cold.

Ronald Maddison: Sarin B was dripped onto his arm

The two-year scientific study will examine the death rates of all volunteers at the chemical and biological warfare research centre since 1939.

And there will be more detailed scrutiny of those exposed to the most dangerous substances.

Several Cornish servicemen were exposed to the deadly nerve gas sarin during experiments between the 1950s and 1980s.

And Wiltshire police investigating their claims have found an unusually high death rate among the volunteers.

The MoD's chemical and biological weapons research centre has tested 3,000 service personnel in human volunteer experiments since 1945.

More than 300 ex-servicemen claim to have suffered disabilities ranging from breathing difficulties to kidney complaints as a result of tests carried out at the centre run by the Defence Evaluation and Research Agency (Dera).

We are convinced that we are sick because of those experiments we took part in
Co-ordinator of the Porton Veterans' Support Group, Ken Earl

The Co-ordinator of the Porton Veterans' Support Group, Ken Earl, said he was "absolutely delighted" by the news of the inquiry.

He told the BBC's Today programme: "There are a lot of very sick people out there and a lot of widows.

"And we are convinced that we are sick because of those experiments we took part in."

The Junior Defence Minister, Dr Lewis Moonie, agreed the tests had been "potentially dangerous" but added that they had been necessary to show what effects nerve gas and nitrogen mustard gas would have on people and whether they could be protected against it.

He told the programme: "We are trying to find out as much as we can from volunteers about what happened to them.

"Anybody who thinks they have been injured or become ill as a result of their military service is entitled to apply for a war pension," he concluded.

Nerve agent

It was revealed earlier this year that a coroner had applied to hold a fresh inquest into the death of an airman who took part in one of the experiments.

It is claimed that 20-year-old Mr Maddison died 45 minutes after 200mg of the deadly nerve agent sarin was dripped onto a patch of uniform taped to his arm at Porton Down.

The original inquest into his death was held 48 years ago behind closed doors, where a coroner concluded he died of asphyxia.

The coroner's report was never released and the only relative allowed into the inquest was the airman's father, who was sworn to silence under the Official Secrets Act.

 Perhaps this common cold research shows that they did know that things like fluorine bearning nerve gases have long term effects in the immunity of the lung and the body, which leads to more colds, flu, diseases.

 We see in Oak Ridge that persons exposed to low level HF have greater rates of lung problems and fatigue.

 Likewise, with sick building syndrome there is the tight building with freon exposure that leads to things like legionaires deaths.