In so far as they authorise the execution of any works on, over or under any highway, the powers conferred on the Development Corporation by section 1 of this Act and this Schedule shall not be exercised without the consent of the highway authority.

Any consent requested for the purposes of sub-paragraph (1) above shall not be unreasonably withheld but may be given subject to such reasonable conditions (other than a condition requiring a monetary payment for the grant of the consent) as the highway authority may impose.

Any question whether such consent is or is not unreasonably withheld, or any conditions so imposed are or are not reasonable, shall be determined by arbitration.