19.—(1) Subject to paragraphs (2) and (5), on receipt of a direction under regulation 18 in which a matter referred to in any of sub-paragraphs (a) to (e) of paragraph (2) of that regulation is specified, the authority to which the direction is given shall immediately—
(a)abandon any arrangements made for the holding of a referendum (whether in consequence of a petition or an earlier direction of the Secretary of State) to the extent that those arrangements are inconsistent with the arrangements necessary to conduct the referendum required by the direction;
(b)abandon all action in respect of any petition received on or before the day on which they receive the direction;
(c)in accordance with paragraphs (1), (2) and (4) of regulation 20, draw up proposals for the operation of executive arrangements;
(d)in accordance with paragraphs (3) and (4) of regulation 20, draw up outline fall-back proposals; and
(e)make arrangements for the holding of a referendum on the proposals drawn up in accordance with sub-paragraph (c) (to the extent required to supplement any arrangements that may continue by virtue of sub-paragraph (a)).
(2) Where, on the day on which the direction is received, the authority—
(a)are in possession of the first petition submitted to them under Part II of these Regulations (including the single petition resulting from an amalgamation of petitions in accordance with regulation 8(1)), and
(b)have not complied with regulation 11(2) in relation to it,
they shall satisfy themselves as to its validity in accordance with Part II of these Regulations; and, subject to paragraph (3)(b), the direction shall be of no further effect.
(3) Where, in a case to which paragraph (2) applies—
(a)the authority are satisfied that the petition is valid, they shall comply with regulation 13; and the direction under regulation 18 shall be treated as revoked with effect from the date on which notice is given under regulation 13(1);
(b)the authority are satisfied that the petition is invalid, they shall comply with regulation 14; and the direction under regulation 18 shall be treated as effective from the date on which notice is given under regulation 14(1).
(4) On receipt of a direction under regulation 18 in which a matter referred to in sub-paragraph (f) or (g) of paragraph (2) of that regulation is specified, the authority to which the direction is given shall immediately take the steps necessary to give effect to the direction.
(5) Where—
(a)the authority to which a direction under regulation 18 has been given receive a petition submitted to them under Part II of these Regulations (including the single petition resulting from an amalgamation of petitions in accordance with regulation 8(1));
(b)the petition is received before they have given notice of the date on which the referendum is to be held pursuant to the direction;
(c)the petition proposes a constitutional change different from that in relation to which the direction requires a referendum to be held; and
(d)the proper officer determines, in accordance with Part II, that the petition is a valid petition,
the direction shall be treated as revoked with effect from the date of the proper officer’s determination.
(6) In a case to which paragraph (5) applies, the authority shall notify the Secretary of State and the petition organiser (if any) of the date of the proper officer’s determination; and shall include that notification in the notification required by regulation 13(1).