Subject to paragraph (2), if the work is not completed within ten years from the coming into force of this Order or such extended time as the Secretary of State may on the application of the authorised officer allow, then on the expiration of that period or such extended time (as the case may be) the powers by this Order granted to the undertaker for making and maintaining the works shall cease except as to so much thereof as is then substantially commenced.

Nothing in paragraph (1) shall apply to any works carried out under paragraph (3) of article 4 (Power to construct works) or article 6 (Subsidiary works).