Top Secret Military Spraying Over Britain - Clouds of Secrecy

Background to Porton Down experiments

During May 1963, the War Office Chief Scientist sent a memo to the Secretary of State explaining the type of public area experiments that were being conducted in the UK by Porton Down. As can be seen in the covering letter, the experiments were conducted in a high level of secrecy because "knowledge of them by unauthorised persons could be politically embarrassing."
Read more: http://www.nr23.net/govt/spray.htm