The Precautionary Principle

This Note provides a brief overview of the Precautionary Principle. It explains what the principle is, what it is not and when it should be applied. There have been many definitions and descriptions of the Precautionary Principle. However, the most widely accepted, and used, definition in the UK was set out in the Declaration of the Rio Conference: "Where there are threats of serious or irreversible damage, lack of full scientific certainty should not be used as a reason for postponing cost-effective measures to prevent environmental degradation".