5(1)Where the Secretary of State—
(a)makes an order under section 7 of the [1959 c. 25.] Highways Act 1959 directing that a highway proposed to be constructed by him shall become a trunk road ; or
(b)makes or confirms an order or scheme under section 9, 11 or 13 of that Act,
any development plan approved or made under this Schedule which relates to land on which a highway is to be constructed or altered in accordance with that order or scheme shall have effect as if the provisions of that order or scheme were included in the plan.
(2)Where an order is made by the Secretary of State under section 1 of the [1965 c. 59.] New Towns Act 1965 designating an area as the site of a new town under that Act, any development plan approved or made under this Schedule which relates to land in that area shall have effect as if the provisions of that order were included in the plan.
(3)Nothing in this paragraph shall be construed as prohibiting the inclusion in a development plan, as approved or made by the Secretary of State or as for the time being amended, of provisions—
(a)defining the line of a highway proposed to be constructed or altered in accordance with any such order or scheme as is mentioned in sub-paragraph (1) of this paragraph ; or
(b)defining an area designated as the site of a new town by any such order as is mentioned in sub-paragraph (2) of this paragraph; or
(c)defining land as likely to be made the subject of any such order or scheme as is mentioned in either of those sub-paragraphs.
(4)Provision may be made by regulations under this Act for enabling any proceedings preliminary to the making of any such order as is mentioned in sub-paragraph (1)(a) or (2) of this paragraph, to be taken concurrently with proceedings required under this Schedule to be taken in connection with the approval or making of a development plan relating to land to which any such order applies, or in connection with any amendment of a development plan rendered necessary or desirable in consequence of any such order.