Licensee excused under specific circumstances

(1) A licensee shall not be held to have violated the provisions of section 71, by reason only of the fact that a discharge from a sewer or works vested in it contravenes the conditions of a permit relating to the discharge if– (a) the contravention is attributable to a discharge into the sewer or works caused or permitted by another person; and (b) the licensee either was not bound to receive the discharge into the sewer or works or was bound to receive it there subject to conditions which were not observed; and (c) the licensee could not reasonably have been expected to prevent the discharge into the sewer or works. (2) A person shall not be held to have violated the provisions of section 71, in consequence of a discharge which he caused or permitted to be made into a sewer or works vested in a licensee if the licensee was bound to receive the discharge there either unconditionally or subject to conditions which were observed. 80 same.