Fears over chemical and germ warfare are on the agenda again as Britain gears up for a possible war with Iraq.

MARTIN VINCENT paid a visit to Porton Down, the top secret chemical and germ warfare centre, and found a group of dedicated scientists determined to let the world know that they had little to hide.

I spoke to technical director Dr Rick Hall (right), who was keen to assure me that Porton Down, which is near Salisbury, did not produce chemical or biological weapons and that it has nothing to hide.

Dr Hall spoke freely about the row over claims that ex-servicemen were duped into taking part in potentially dangerous experiments at Porton Down after volunteering for what they thought were tests to find a cure for the common cold.

Wiltshire Coroner David Masters is still awaiting a final High Court decision on whether he can re-open the inquest into the death of an RAF mechanic who died 49 years ago after being tested with a nerve agent.

Ronald Maddison was just 20 when he died shortly after the poison Sarin was applied to his clothing during the experiment.

Later, several hundred veterans including four from Swindon complained that they had been tricked into taking part in similar experiments.

Their complaints are part of a Wiltshire police inquiry that has been going on for nearly four years.

Dr Hall said: "We understand clearly that what we do is a very emotive and emotional business. We do not have offensive capabilities and very little of what we do is highly classified.

"But obviously we would not publish 'how to do it manuals' to make it easy for people to do their own thing."

He said Porton Down had been totally free and open with the police, who come and go as they please. "They have permanent passes to everything, including classified information.

"Wiltshire police have already put their case to the coroner and not surprisingly we do not agree with all of it.

"Of the six people to take part in that particular experiment which involved a nerve agent, Mr Maddison was the only one affected and unfortunately died.

"It is expected that the High Court will make a final decision in November on whether the inquest can be reopened."

Porton Down was opened on a remote stretch of open farmland in 1916 as a direct response to the threat from Germany to use gas on British troops in the trenches during World War One.

As well as developing protective measures against a chemical attack, Porton Down was, until the mid-1950s, concerned with the development of a major retaliatory capability in chemical warfare.

But, stressed Dr Hall, since then the only research has been on defensive measures.

"The UK has signed various conventions which make it illegal for us to pursue offensive activities," he said.

"We have no capability for chemical or biological weapons. There are no production facilities or weapons filling plants and we are regularly checked on this.

"The important priority research we carry out on this site is the detection and identification of micro organisms (germs) and the development of medical counter measures and treatment against them."

Porton Down is run for the Ministry of Defence by the Defence Science and Technology Laboratory and more than 800 people work there.

Dr Hall said the scientists were proud of the work they had done developing protection for British troops who may be attacked by biological or chemical weapons.

"If Saddam Hussein had used nerve agents in the Gulf War we do not believe there would have been many casualties among UK forces," he said. "They are among the best protected in the world and we continually work to improve that protection."

Many of the protective and precautionary measures Dstl develops for the military are also used to improve the health of the civilian population.