Wiltshire Police have prepared a file for the coroner after investigating circumstances at Porton Down where Ronald Maddison was allegedly administered a fatal dose of nerve gas.

Mr Maddison was among a group of servicemen and women who say they were used as guinea pigs in germ warfare experiments at the Chemical and Biological Defence Establishment on Salisbury Plain.

It is claimed Mr Maddison died after 200mg of the deadly nerve agent Sarin, was dripped onto a patch of uniform taped to his arm.

The coroner will no doubt consider if there has been a conspiracy by government to hide the truth given that the 1953 inquest was held in secret and kept secret for many years Alan Care Solicitor

An inquest into the death of the 20-year-old airman was held in private in 1953 for reasons of "national security."

Detectives have also been examining evidence from other servicemen and women who say they were tricked into taking part in dangerous experiments with substances including LSD, the hallucinogenic drug.

Wiltshire Coroner David Masters said: "The coroner is aware, of course, of the ongoing inquiry being conducted by the Wiltshire Constabulary and is given to understand that he will receive a report by the end of January next year."

Alan Care, a Litigation Executive from Thomas Snell and Passmore, who represent the relatives of the Porton Down victims, said: "The only reason I can see to re-open this inquest is for the coroner and jury to consider an unlawful killing verdict.

"I cannot envisage anything more serious for the Ministry of Defence who ran Porton Down for many years.

Ronald Maddison: Sarin B was dripped on to his arm

"The coroner will no doubt consider if there has been a conspiracy by government to hide the truth given that the 1953 inquest was held in secret and kept secret for many years."

Wiltshire Police said the move was only being made after consulting Mr Maddison's family.

The Ministry of Defence'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).