Subject to subsection (2) below, any person who causes or knowingly permits to flow, or puts or knowingly permits to be put, into any waters containing fish or into any tributaries of waters containing fish, any liquid or solid matter to such an extent as to cause the waters to be poisonous or injurious to fish or the spawning grounds, spawn or food of fish, shall be guilty of an offence.

A person shall not be guilty of an offence under subsection (1) above for any act done in the exercise of any right to which he is by law entitled or in continuance of a method in use in connection with the same premises before 18th July 1923, if he proves to the satisfaction of the court that he has used the best practicable means, within a reasonable cost, to prevent such matter from doing injury to fish or to the spawning grounds, spawn or food of fish.

Proceedings under this section shall not be instituted except by the water authority F1 . . .or by a person who has first obtained a certificate from the Minister that he has a material interest in the waters alleged to be affected.