(1) It shall not be lawful for a person to drive a motor vehicle on a restricted road at a speed exceeding 30 miles per hour.
(2) The national authority may by order ... increase or reduce the rate of speed fixed by subsection (1) above, either as originally enacted or as varied under this subsection.
(3) An order under subsection (2)—
(a) if made by the Secretary of State, is to be made by statutory instrument and approved by a resolution of each House of Parliament;
(aa) if made by the Welsh Ministers, is to be made by statutory instrument and approved by a resolution of the National Assembly for Wales;
(b) if made by the Scottish Ministers, is subject to the affirmative procedure.
(4) Before making an order under subsection (2) the Secretary of State must consult with the Welsh Ministers and the Scottish Ministers.
(5) Before the Welsh Ministers or the Scottish Ministers make an order under subsection (2) they must consult with the Secretary of State.