19.—(1) An authority or person consulted under article 17 or 18 must give a substantive response to that consultation before the end of the period of 21 days beginning with the day on which—
(a)the document on which the authority or person’s views are sought; or
(b)where there is more than one such document and they are sent on different days, the last of those documents,
is received by the consultee, or such other period as may be agreed in writing between the consultee and the Secretary of State.
(2) For the purposes of this article, a substantive response is one which—
(a)states that the consultee has no comment to make;
(b)states that, on the basis of the information available, the consultee is content with the development proposed;
(c)refers the Secretary of State to current standing advice by the consultee on the subject of the consultation; or
(d)provides advice to the Secretary of State.