Mr Maddison thought he was helping find a cure for the common cold, say his family

A lawyer said the government would not be protected from liability after an airman died who had been taking part in chemical tests, an inquest has heard.

Ronald Maddison, 20, died after being exposed to Sarin in May 1953 during an experiment at Porton Down, Wiltshire.

Later, the Treasury Solicitor wrote to an official in the Ministry of Supply.

He said the Ministry and the Crown were not protected from liability as gas could not be deemed "a supply used for the purposes of the armed forces".

And, therefore, the 1947 Crown Proceedings Act did not offer protection from liability.

The letter by Mr H Woodhouse also revealed high level concern that the case should not be heard in court, if the family did take legal action.

Indeed it is difficult to see how it was ever possible to say truthfully that tests with lethal gases did not contain 'the slightest chance of danger' Treasury Solicitor letter

"A claim by Maddison's representatives against the Ministry for negligence could not be an easy case for them to substantiate.

"But I imagine that if they did start such proceedings, the Ministry would wish to settle rather than to have the whole case ventilated in court."

The solicitor also proposed paying a pension to the family on the assumption that they would have no other claim for compensation.

"This would probably dispose of the case completely and LAC Maddison's relatives would probably be satisfied," Mr Woodhouse added in his letter.

The letter was read out as the solicitor for the Maddison family, Gerwyn Samuel, continued his questioning of Ministry of Defence historian John Harding.

'Misleading'

Mr Harding told the hearing that he could not recall coming across any evidence of compensation having been paid to LAC Maddison's relatives.

In another letter from Mr Woodhouse in May 1953, it was acknowledged that it would be a good idea in future to arrange for volunteers to undergo a medical examination at Porton Down by doctors aware of the nature of the tests.

The letter read: "The sentence 'tests are carefully planned to avoid the slightest chance of danger' have proved misleading.

"Indeed it is difficult to see how it was ever possible to say truthfully that tests with lethal gases did not contain 'the slightest chance of danger"'.

The inquest, being held at Trowbridge, is a reopening of one held in 1953 on the orders of the then home Secretary Sir David Maxwell-Fyfe which recorded a verdict of death by misadventure.

The inquest continues.