For more than half a century, the final, agonising minutes of Ronald Maddison's life remined as secret as the nerve gas test that killed him. Dan Jenkins looks at an inquest that revealed the truth behind both his horrific death and the treatment his family suffered afterwards.

HE last minutes of Ronald Maddison's life read like something out of a Cold War science fiction novel - a young man placed in a chair by faceless scientists in protective suits, then killed with a mere drop of a clear liquid.

The gruesome details of the nerve gas test that killed him were known in 1953, but the original inquest into his death was held in secret.

The second, exhaustive inquest, which finished yesterday, not only brought them to light, but has also given the public a rare insight into how the post-war military establishment used servicemen as human guinea pigs.

LAC Maddison thought he had nothing to fear when he signed up as a volunteer for military experiments in 1953.

The 20-year-old believed he was doing nothing more risky than helping to find a cure for the common cold - and was perhaps lured by the 15 shillings in extra pay the trip to Porton Down promised.

But his time in the gas chamber at the secretive chemical weapons research facility in Wiltshire proved agonisingly short.

Scientists dripped 200mg of the deadly agent Sarin onto his arm and he collapsed within seconds.

One of those who witnessed his death throes was ambulance driver Alfred Thornhill, then only 19 and completing his National Service. The horrors of the scenes have been burned into his memory.

During this year's second inquest, he described to the jury how he first saw LAC Maddison.

"He was convulsing and foam was coming out of his mouth," he said. "Then he was taken into the medical centre, where there were scientists and medical people.

"They just threw him on to the bed and gave him a big injection. It was a terrible atmosphere - they were all panicking. They couldn't handle what they were looking at."

BEFORE the hearing, he had broken his 50-year silence to tell how LAC Maddison looked like he had frog spawn coming out of his mouth, and twitched as if he were being electrocuted. Mr Thornhill also witnessed how LAC Maddison's leg gradually turned blue and rose of its own accord off the bed.

"I had never seen anyone die before and what that lad went through was absolutely horrific," he said.

He was ordered to take the body to the mortuary at Salisbury General Hospital - and told to take the back roads. Later, he was summoned by a medical officer. "He made me sign something and told me if I ever spoke a word about what I saw at Porton Down, I would be sent to prison."

LAC Maddison was one of six servicemen who entered the chamber at Porton Down, wearing respirators. All were exposed to 200mg of Sarin, dropped onto a piece of uniform material loosely wrapped around their arms.

The inquest heard how he and a colleague sat in the chamber in their masks playing noughts and crosses while they were under observation. After 23 minutes, he said he felt "pretty queer" and was taken outside, where he began to experience breathing difficulties and was sweating.

He was given an antidote but his condition worsened and he said he could not hear.

Also in the group being tested was Michael Cox, who said he saw LAC Maddison slump forward in his chair after he was exposed to drops of Sarin. He described how his colleague was carried out, but the tests went on.

Speaking after the hearing, he said: "I know now that, far from there being very little risk, there was a great risk and Ronnie paid the price."

The pair had volunteered to take part in the trials after seeing notices posted at their RAF bases that assured those taking part would come to no harm.

How much the scientists knew before they gave LAC Maddison his fatal dose will never be known, although one expert told the inquest that the scientists had not taken into account the volunteers' surface skin fat content, a key factor in the effect Sarin has. Later tests showed LAC Madison's skin fat was virtually absent.

The way the MoD acted after Maddison's death shows how terrified they were.

Mr Thornhill described how, the day after the lethal experiment, the ward where he died reeked of disinfectant, as if it had been swabbed from floor to ceiling.

His body was sent back to his family in Consett, County Durham, in a sealed, lead-lined coffin and his father, John Maddison, was told only that his son had died on a matter of national security.

But he later wrote a letter to military chiefs, in which he rejected an offer of £3 towards funeral expenses, saying: "I would like to know a bit more about my son's death as I am not satisfied with what I have been told."

Mr Maddison and his wife both died long before Wiltshire Police ever began the investigation that led to the second inquest. And the strain proved so great that Ronnie's sister, Lillias Craik, suffered a stroke during the hearing.

His cousin, Ella Forster, who still lives in Shotley Bridge, near Consett, is also a frail and elderly woman.

When interviewed by The Northern Echo earlier this year, she remembered Ronnie as a quiet, well-behaved and good-natured boy. There were tears in her eyes but still a note of steel in her voice, the determination to see justice held fast over decades, that finally reached its conclusion yesterday.

And the verdict of unlawful killing also leaves the way open for the family to seek compensation far above the £3 the MoD first offered.