At the end of section 14 of the [1961 c. 33.] Land Compensation Act 1961 (assumptions as to planning permission) there is added—
“(5)If, in a case where—
(a)the relevant land is to be acquired for use for or in connection with the construction of a highway, or
(b)the use of the relevant land for or in connection with the construction of a highway is being considered by a highway authority,
a determination mentioned in subsection (7) of this section falls to be made, that determination shall be made on the following assumption.
(6)The assumption is that, if the relevant land were not so used, no highway would be constructed to meet the same or substantially the same need as the highway referred to in paragraph (a) or (b) of subsection (5) of this section would have been constructed to meet.
(7)The determinations referred to in subsection (5) of this section are—
(a)a determination, for the purpose of assessing compensation in respect of any compulsory acquisition, whether planning permission might reasonably have been expected to be granted for any development if no part of the relevant land were proposed to be acquired by any authority possessing compulsory purchase powers, and
(b)a determination under section 17 of this Act as to the development for which, in the opinion of the local planning authority, planning permission would or would not have been granted if no part of the relevant land were proposed to be acquired by any authority possessing compulsory purchase powers.
(8)The references in subsections (5) and (6) of this section to the construction of a highway include its alteration or improvement.”