(1)The provisions of this section shall have effect where an application is made for listed building consent for the alteration or extension of a listed building and—
(a)either the works do not constitute development or they do so but the development is such that planning permission therefor is granted by a development order; and
(b)the Minister, either on appeal or on the reference of the application to him, refuses such consent or grants it subject to conditions.
(2)If, on a claim made to the local planning authority within the prescribed time and manner, it is shown that the value of the interest of any person in the land is less than it would have been if listed building consent had been granted, or had been granted unconditionally, as the case may be, the local planning authority shall pay to that person compensation of an amount equal to the difference.
(3)In determining, for the purposes of subsection (2) above, whether or to what extent the value of an interest in land is less than it would have been if the permission had been granted, or had been granted unconditionally,—
(a)it shall be assumed that any subsequent application for the like consent would be determined in the same way ; but
(b)if, in the case of a refusal of listed building consent, the Minister, on refusing that consent, undertook to grant such consent for some other works to the building in the event of an application being made in that behalf, regard shall be had to that undertaking.
(4)No compensation shall be payable under this section in respect of an interest in land in respect of which a purchase notice is served, whether under section 129 or 135 of the principal Act or under section 42 above, being a purchase notice which takes effect.