Changes to Control of Pollution (Exemption of Certain Discharges from Control) 1983
S.I. 1983/1182
Made by Control of Pollution (Exemption of Certain Discharges from Control) (Variation) 1986
3 changes. All changes to Control of Pollution (Exemption of Certain Discharges from Control) 1983
From legislation.gov.uk's record of changes, the official one: see it there.