Paragraph 9 I1

In addition to any requirement under article 18 (lights on tidal works, etc.), the Harbour Authority shall, at or near every tidal work, and any other work of which the Harbour Authority is in possession in exercise of any of the powers of this Order (being in either case a work which is below mean high water level forming part of the river), exhibit such lights, lay down such buoys and take such other steps for preventing danger to navigation as the PLA may from time to time reasonably require.