20.—(1) Subject to paragraphs (3) to (5), in the circumstances specified in paragraph (2) the planning authority must publish a notice in the form set out in Schedule 4 in a newspaper circulating in the locality in which the neighbouring land is situated.
(2) The circumstances are—
(a)it is not possible for the planning authority to carry out notification in terms of regulation 18 because there are no premises situated on the neighbouring land to which the notification can be sent;
(b)the applicant has submitted with an application for planning permission under regulations 9, 10 or 11 a certificate issued under regulation 15(2)(b)(iii);
(c)the application is made under regulation 9, 10 or 11 and relates to development of one or more of the classes of development specified in Schedule 3, or
(d)the application is made under regulation 9, 10 or 11 and relates to development which does not accord with the provisions of the development plan.
(3) Paragraph (2)(a) does not apply where—
(a)all the neighbouring land referred to in that paragraph is owned by the planning authority or by the applicant; or
(b)the application relates to householder development.
(4) The planning authority are not required to publish a notice in accordance with paragraph (1) where a notice is required to be published by the planning authority in accordance with section 60(2)(a) (publicity for applications affecting setting of listed buildings) or 65(2)(a) (publicity for applications affecting conservation areas) of the Listed Buildings Act.
(5) Where any of paragraphs (2)(a) to (d) apply but notice has already been published with respect to the application under paragraph (1) the planning authority are not required to publish a further notice.