A CORONER made a series of errors when an inquest ruled a North-East airman was unlawfully killed during secret nerve gas experiments, the Ministry of Defence said yesterday.

Ministers revealed for the first time why they are challenging November's verdict in the case of 20-year-old Ronald Maddison, from Consett, County Durham.

Leading Aircraftman Maddison died in 1953, after the agent sarin was dropped on to his arm at the Porton Down chemical warfare testing facility, in Wiltshire.

The November ruling overturned a misadventure verdict recorded by an inquest held behind closed doors on the orders of Winston Churchill's government.

It paved the way for Mr Maddison's family and hundreds of servicemen subjected to experiments at Porton Down between 1939 and 1989, to seek compensation.

Just before Christmas, the MoD apologised and said it would look favourably at any bid for compensation, but announced the intention to seek a judicial review.

Yesterday, during a Commons debate on Porton Down, Defence Minister Ivor Caplin criticised Wiltshire coroner David Masters for his conduct of the inquest.

He said the MoD was appealing "on the grounds of the coroner's legal rulings, his summing up and his directions to the jury".

* The Wiltshire inquest heard claims that military personnel were tricked into taking part in what they believed were tests to find a cure for the common cold.