Ronald Maddison died after an experiment at Porton Down

Defence Minister Ivor Caplin said on Tuesday that the MoD would seek a judicial review.

Mr Maddison died after sarin nerve gas was used on him during apparent tests for the common cold at the Porton Down base, Wiltshire, 1953.

The MoD said it would also consider "favourably" any compensation claims.

The original inquest, which was held in secret, reached a verdict of misadventure.

Apology

A second inquiry was launched in May 2004 following an inquiry by Wiltshire Police.

The verdict of unlawful killing was reached more than six months later in November.

In a written statement Mr Caplin said: "I wrote yesterday to solicitors acting for the Maddison family apologising... [for] proceeding with a test involving Ronald Maddison.

"This was undertaken notwithstanding the fact that an identical test on May 4, 1953, resulted in an adverse blood reaction in one serviceman."

He went on to say that the family had not yet lodged a claim for compensation, but added that any claim would be "considered favourably on the basis of the negligence referred to above."

The statement also added that the MoD intended to "challenge by way of judicial review the inquest verdict of unlawful killing."

News of the MoD's intention to appeal was greeted with a barrage of criticism from veterans.

Say sorry

Former RAF serviceman Ken Earl, 71, of Maidstone, Kent, who underwent the same sarin test as Mr Maddison, said he was "horrified" at the MoD's challenge.

"I'm flabbergasted that they could even think about it - it's unbelievable," he said.

"The inquest sat for six months, 64 days in court, over 4,000 documents, more than 100 witnesses.

"The jury came back with a unanimous verdict after just five hours but the MoD cannot accept it. I'm horrified they could even consider this."

Mr Earl said he sat in the same chair inside a gas chamber that Mr Maddison occupied two days later.

Former Royal Navy serviceman Eric Gow, 69, from Merseyside, who underwent tests at the base in January 1954 and now runs the Porton Down Veterans Support Group, said: "After the verdict was recorded, the Maddison family would have expected not to have to continue fighting.

"It's such a shame that they have to. In fact the shame lies with the government.

"It's an absolute waste of taxpayers' money," he added.