3(1)Not later than the date on which the said notice is first published as aforesaid, the river purification board shall serve a copy thereof (together with a copy of the application and of any relevant map or plan) on the following-
(a)every local authority whose area is comprised wholly or partly in the proposed control area ;
(b)any statutory body the exercise of whose functions may be affected by the control order if made ;
(c)any body or association appearing to the river purification board to represent persons who in their opinion may be affected by the control order if made ; and
(d)every person known to the river purification board to have any interest in any land to which the control order applied for would relate:
Provided that where it appears to the Secretary of State, from representations made to him by the board, that compliance with head (d) of this sub-paragraph would be unduly onerous, it shall be sufficient compliance if the board, having submitted proposals in this regard to the Secretary of State, take such steps as he may direct as respects service of the said copy documents upon such of the persons referred to in the said head (d) as in his opinion may be materially affected by the control order if made, and as respects further publication of those documents.
(2)In this paragraph the expression " statutory body" means any body exercising functions conferred on it by or under any enactment.