(b) to secure that its efficiency for flood defence purposes is not impaired and that the risk of flooding is not otherwise increased, 

by reason of any specified work. 

19. —(1) Subject to sub-paragraph (2), any specified work, and all protective works required by the drainage authority under paragraph 18, must be constructed— 

(a) without unnecessary delay in accordance with the plans approved or settled under this Part of this Schedule; and 

(b) to the reasonable satisfaction of the drainage authority, 

and an officer of the drainage authority is entitled to watch and inspect the construction of such works. 

(2) Network Rail must give to the drainage authority not less than 14 days’ notice in writing of its intention to commence construction of any specified work and notice in writing of its completion not later than 7 days after the date on which it is completed. 

(3) If any part of a specified work or any protective work required by the drainage authority is constructed otherwise than in accordance with the requirements of this Schedule, the drainage authority may by notice in writing require Network Rail at Network Rail’s own expense to comply with the requirements of this Part of this Schedule or (if Network Rail so elects and the drainage authority in writing consents, such consent not to be unreasonably withheld or delayed) to remove, alter or pull down the work and, where removal is required, to restore the site to its former condition to such extent and within such limits as the drainage authority reasonably requires. 

(4) Subject to sub-paragraph (6) and paragraph 23, if within a reasonable period, being not less than 28 days from the date when a notice under sub-paragraph (3) is served upon Network Rail, it has failed to begin taking steps to comply with the requirements of the notice and subsequently to make reasonably expeditious progress towards their implementation, the drainage authority may execute the works specified in the notice and any expenditure incurred by it in so doing is recoverable from Network Rail. 

(5) In the event of any dispute as to whether sub-paragraph (3) is properly applicable to any work in respect of which notice has been served under that sub-paragraph, or as to the reasonableness of any requirement of such a notice, the drainage authority must not except in an emergency exercise the powers conferred by sub-paragraph (4) until the dispute has been finally determined. 

(6) If by reason of construction of the specified work the Agency’s access to flood defences or equipment maintained for flood defence purposes is materially obstructed, Network Rail must provide such alternative means of access to allow the Agency to maintain the flood defence or use the equipment no less effectively than before the obstruction. 

20. —(1) Subject to sub-paragraph (5) Network Rail must from the commencement of the construction of the specified works maintain in good repair and condition and free from obstruction any drainage work which is situated within the limits of deviation and on land held by Network Rail for the purposes of or in connection with the specified works, whether or not the drainage work is constructed under the powers conferred by this Order or is already in existence. 

(2) If any such drainage work which Network Rail is liable to maintain is not maintained to the reasonable satisfaction of the drainage authority, the drainage authority may by notice in writing require Network Rail to repair and restore the work, or any part of such work, or (if Network Rail so elects and the drainage authority in writing consents, such consent not to be unreasonably withheld or delayed), to remove the work and restore the site to its former condition, to such extent and within such limits as the drainage authority reasonably requires. 

(3) Subject to sub-paragraph (5) and paragraph 23, if, within a reasonable period being not less than 28 days beginning with the date on which a notice in respect of any drainage work is served under sub-paragraph (2) on Network Rail, Network Rail has failed to begin taking steps to comply with the reasonable requirements of the notice and has not subsequently made reasonably expeditious progress towards their implementation, the drainage authority may do what is 

