MILITARY scientists who tested nerve agents on unwitting servicemen at the Government's Porton Down chemical weapons unit will not face criminal charges.

Wiltshire detectives spent three years investigating the unit, and at the conclusion of the £2 million operation Antler, they recommended that charges be brought against three former scientists who worked there.

But now the Crown Prosecution Service has said there is insufficient evidence to prosecute the trio.

The decision may prove controversial depending on the verdict of an inquest which opens in September into the death of 20-year-old Ronald Madison who died after drops of the nerve agent Sarin were placed on his skin by Porton Down scientists.

Tests on thousands of service personnel involving nerve agents and drugs were carried out between 1953 and 1983. Many were encouraged to volunteer by the promise of an extra two shillings pay and a 48-hour leave pass.