Section 43I of the Principal Act is amended as follows:

(a) by omitting from subsection (4)(b) "years." and substituting "years; or" ;

(b) by inserting the following paragraph after paragraph (b) in subsection (4) :

(c) if the planning authority has granted a further extension under subsection (6) , at the end of a further period of 2 years from the end of the further period of 2 years for which the permit was extended under subsection (4A) .

(c) by inserting the following subsections after subsection (5) :

(6)  If the use or development in respect of which a permit was granted is not, or is unlikely to be, substantially commenced before the permit would otherwise lapse under subsection (4)(b) , the planning authority may grant (once only) a further extension of the period during which that use or development must be substantially commenced.

(7)  An application may be made under subsection (4A) or (6) , for an extension of a period during which a use or development in respect of which a permit was granted must be substantially commenced, at any time before the end of the period of 6 months from the day on which the permit has lapsed and, if the extension is granted, the permit is to be taken to not have lapsed on that day.