3. On the day appointed by article 2, the following provisions of the Town and Country Planning Act 1990 (“the 1990 Act”)(1) cease to have effect in relation to Wales—
(a)section 12 (preparation of unitary development plan);
(b)section 21 (alteration or replacement of unitary development plan); and
(c)section 23B (unitary development plans for National Parks in Wales).