16.—(1) Subject to paragraphs (2) and (3) and regulation 21, a referendum in consequence of a valid petition shall be held not later than—
(a)the end of the period of six months beginning with the petition date; or
(b)the end of the period of two months beginning with the date on which regulations under section 45 (with respect to the referendum) come into force,
whichever is the later.
(2) A referendum shall not be held before the end of the period of two months beginning with the date on which proposals are sent to the Secretary of State in accordance with regulation 17(9).
(3) Paragraph (1) shall not apply where the Secretary of State holds a referendum in exercise of the power conferred by regulation 25.