A FAMILY has won its 50-year fight for justice, after an inquest ruled the death of an airman during secret nerve gas experiments was unlawful.

Leading Aircraftman Ronald Maddison, 20, of Consett, died in May 1953 after being exposed to the deadly nerve gas sarin during experiments at Porton Down chemical warfare testing centre in Wiltshire.

On Monday, a second inquest into his death returned a verdict of unlawful killing. LAC Maddison's family now plans to seek compensation, and the ruling opens doors to hundreds of other servicemen subjected to Porton Down experiments between 1939 and 1989. The initial inquest into LAC Maddison's death, held in secret, had recorded a verdict of misadventure.

But after years of campaigning by the family, an inquiry was launched by Wiltshire Police in 1999 and in 2002 and Lord Chief Justice Woolf granted permission for the second inquest.

The Father of the House of Commons, Labour MP Tam Dalyell, who has campaigned on the issue of Porton Down for decades, said he sympathised with veterans' calls for a public inquiry into the research and called for some kind of pay-out for them.

During the inquest in Trowbridge, Wiltshire, LAC Maddison's family claimed he and other military personnel were duped into taking part in what they believed were harmless experiments to find a cure for the common cold.

The court heard how the test that claimed his life took place just nine days after a similar experiment resulted in the near-fatal poisoning of another volunteer, soldier James Kelly. But lawyers for the MoD said all servicemen who underwent experiments at Porton Down were told beforehand.

Terry Alderson, 74, of Danby, near Whitby, said he was delighted with the jury's decision.

"We have got a result for the Maddison family. We were sent in there like sheep. They treated us like human animals and we that are still alive are the lucky ones."

A spokesman for the MoD said: ''The Ministry of Defence notes the jury's findings and will now take some time to reflect on these. We will be seeking legal advice on whether we wish to consider a judicial review.

"We don't believe the verdict today has implications for other volunteers.

Porton Down volunteer Terry Alderson said outside the court: "It was Russian Roulette, Ronald Maddison was just the first. Our health was never monitored afterwards and nobody knows how many died."