In this Part, existing discharge means a discharge of trade effluent from trade premises into the sewers or sewage treatment works of a local authority which was lawfully made within the period of two years ending on 1st October 1973.

Where before 1st October 1973 a local authority and the person making the discharge have agreed that after that date the nature or composition of the discharge may be altered or the temperature, volume or rate of discharge may be increased, any discharge made in accordance with such agreement shall be treated for the purposes of this Part as an existing discharge.

Any dispute between the Ministry and the person making the discharge as to whether the discharge is an existing discharge shall be determined by the county court whose decision in the matter shall be final, except on a point of law.