25(1)Where a lease is varied so as to increase the amount of rent as from a date before the end of the fifth year of the term of the lease, the variation is treated for the purposes of this Act as if it were the grant of a lease in consideration of the additional rent made payable by it.
(2)Sub-paragraph (1) does not apply to an increase of rent in pursuance of—
(a)a provision contained in the lease before it was varied, or
(b)a provision mentioned in paragraph 10(6)(a) or (b) (variations of certain agricultural leases).