A CORONER will today ask the High Court to allow him to reopen an inquest into the death of an ex-serviceman from a deadly chemical.

Ronald Maddison, of Consett, County Durham, died aged 20 nearly 50 years ago, after he was exposed to the lethal nerve agent Sarin at the Government's Porton Down chemical and biological weapons research laboratory, while serving in the RAF.

The original inquest, held in secret, concluded that Mr Maddison died of asphyxia.

But in recent years, a campaign has been launched by former servicemen who claim they were unwitting volunteer guinea pigs for chemical weapons tests, having been told they were aiding research for cold cures.

Wiltshire Police, the force which covers Porton Down, has been investigating the claims.

Today, at the High Court in London, Wiltshire and Swindon Coroner David Masters will ask for permission to re-open the inquiry into Mr Maddison's death.

A spokeswoman for Wiltshire Police said Mr Masters had announced earlier this year that he wanted the inquest reopened "on the grounds of insufficiency of inquiry and the discovery of new facts and evidence".

Porton Down campaigners hope a fresh inquest into his death will return a verdict of unlawful killing.

At a preliminary hearing in July, Ministry of Defence lawyer Jason Beer said the ministry would not oppose the coroner's application but "might wish to assist the court on some evidential matters".

The judges will have to decide whether it is now in the public interest for a new inquest to be held.

Mr Maddison was one of a number of servicemen who volunteered to take part in experiments at Porton Down.

The coroner's barrister, Mr Ian Burnett QC, told the High Court in July that the experiments involved placing Sarin liquid on to the clothed and unclothed skin of the volunteers.

On May 6, 1953, 200mg was applied to Mr Maddison's clothed forearm, resulting in rapid signs of acute toxicity. Despite attempts at resuscitation, he was soon dead.

Mr Maddison's sister, Lillias Craik, who now lives in Nottinghamshire, has welcomed the coroner's move.