If the Secretary of State is satisfied that it is necessary to remedy a substantial injury to the amenity of the locality or a danger to members of the public, she may serve a discontinuance notice under regulation 8 in relation to an advertisement displayed by an interested planning authority.

Paragraphs (3) and (6) of regulation 8 shall apply in relation to a discontinuance notice served under paragraph (1) as they apply in relation to a discontinuance notice served by a local planning authority as if for references to the local planning authority there were substituted references to the Secretary of State.

Paragraph (3) of regulation 17 shall apply in relation to a discontinuance notice served under paragraph (1) as it applies in relation to a discontinuance notice served by a local planning authority, with such modifications as may be necessary.