secure that so much of the works authorised by this Act as is constructed under any highway must be so designed, constructed and maintained as to carry the appropriate loading recommended for highway bridges by the Secretary of State at the time of construction of the works, and

indemnify the highway authority against, and make good to the highway authority, the expenses which the highway authority may reasonably incur in the maintenance or repair of any highway, or any tunnels, sewers, drains or apparatus in the highway, by reason of non-compliance with the provisions of this paragraph.