Military service veterans protested today as the Ministry of Defence reached a settlement over an inquest verdict with the family of an RAF serviceman who underwent lethal nerve gas tests more than 50 years ago.

Leading Aircraftsman Ronald Maddison, from Consett, County Durham, died aged 20 after having droplets of sarin dabbed on to his arm at Porton Down chemical warfare testing facility on Salisbury Plain, Wiltshire, in 1953.

The MoD was due to challenge a Wiltshire inquest jurys unlawful killing verdict returned in November 2004.

The case was settled when the MoD agreed to accept the verdict on the basis that Mr Maddison had died as a result of gross negligence in respect of the conduct and planning of the experiment.

But it successfully argued that the unlawful killing verdict could not imply that Mr Maddison did not consent to the experiment or there had been a failure to obtain his consent.

The 400-strong Porton Down Veterans Group says todays settlement smothers evidence that Mr Maddison never gave his informed consent to the test which killed him.