WWII poison darts secret emerges

Lethal clouds of tiny poisoned darts were to be tipped with mustard gas to kill enemy troops without damaging nearby buildings or equipment.

The file has been released by the National Archives.

Test results were inconclusive and although the scientists remained enthusiastic, the project was shelved.

The concept was developed between 1941 and 1945 at the Porton Down research base in Wiltshire.