13.—(1) The risk must be characterised by combining, for each potential adverse effect, the magnitude with the likelihood of that adverse effect occurring to provide a quantitative or semi quantitative estimation of the risk.
(2) Where a quantitative or semi quantitative estimation is not possible, a qualitative estimation of the risk must be provided. In that case, a categorical description (‘high’, ‘moderate’, ‘low’ or ‘negligible’) of the risk must be used and an explanation of the scale of effect represented by each category must be provided.
(3) Where relevant, the uncertainty for each identified risk must be described and, where possible, expressed in quantitative terms.]