s9 of the Perpetuities and Accumulations Act 1968
(1) Where a disposition is limited by reference to the attainment by any person or persons of a specified age exceeding twenty-one years and it is apparent at the time the disposition is made or becomes apparent at a subsequent time-
(a) that the disposition would apart from this section be void for remoteness; but
(b) that it would not be so void if the specified age had been twenty-one years-
the disposition shall be treated for all purposes as if instead of being limited by reference to the age in fact specified it had been limited by reference to the age nearest to that age which would if specified instead, have prevented the disposition from being so void.
(2) Where in the case of any disposition different ages exceeding twenty-one years are specified in relation to different persons-
(a) the reference in paragraph (b) of subsection (1) to the specified age shall be construed as a reference to all the specified ages; and
(b) that subsection shall operate to reduce each such age so far as is necessary to save the disposition from being void for remoteness.
(3) Where the inclusion of any persons being potential members of a class or unborn persons who at birth would become members or potential members of the class prevents the foregoing provisions of this section from operating to save a disposition from being void for remoteness those persons shall thenceforth be deemed for all the purposes of the disposition to be excluded from the class and the said provisions shall thereupon have effect accordingly.