(1)In this Part of this Act " the parties directly concerned ", in relation to an interest in land, means the person entitled to the interest and the authority by whom it is proposed to be acquired.
(2)For the purposes of sections 25 and 26 of this Act, an interest in land shall be taken to be an interest proposed to be acquired by an authority possessing compulsory purchase powers in the following (but no other) circumstances, that is to say—
(a)where, for the purposes of a compulsory acquisition by that authority of land consisting of or including land in which that interest subsists, a notice required to be published or served in connection with that acquisition, either by an Act or by any Standing Order of either House of Parliament relating to petitions for private bills, has been published or served in accordance with that Act or Order; or
(b)where a notice requiring the purchase of that interest has been served under any enactment, and in accordance with that enactment that authority are to be deemed to have served a notice to treat in respect of that interest; or
(c)where an offer in writing has been made by or on behalf of that authority to negotiate for the purchase of that interest.
(3)For the purpose of determining whether an application can be made at any time in relation to any land under section 25(1) or under section 27 of this Act, any reference in the said section 25(1) to the development plan shall be construed as a reference to a development plan comprising that land, in the form in which (whether as originally approved or made by the Secretary of State or as for the time being amended) that plan is in force at the following time, that is to say, where neither of the following paragraphs apply, the time of the application, and—
(a)where the interest in question is to be acquired in the circumstances mentioned in subsection (2)(b) of this section or the acquiring authority (otherwise than in those circumstances) have served a notice to treat in respect of that interest; or
(b)where the acquiring authority have entered into a contract for the purchase of that interest,
the date of service of the notice to treat or the date of the contract or, where both paragraphs apply, the later of those dates.