6(1)For the purpose of calculating the profits of the lessor under the lease for a period of account—U.K.
(a)that ends on or after the relevant date, and
(b)that is not within paragraph 5(2),
treat the lessor as receiving for that period of account income attributable to the lease of an amount equal to the relevant amount (in addition to any amount brought into account under section 502B(2) of ICTA or section 148A(2) of ITTOIA 2005).
(2)The “relevant amount” is an amount equal to so much of the rentals as—
(a)become due on or after the relevant date, and
(b)are due wholly or partly in respect of the period of account,
as would not reasonably be regarded as reflected in the rental earnings for that period of account.
(3)If any rental is paid for a period (“the rental period”) which—
(a)begins before the relevant date, or
(b)is not wholly within the period of account,
for the purposes of sub-paragraph (2) treat the amount of that rental as equal to the amount apportioned (on a time basis) in respect of so much of the rental period as falls on or after the relevant date and within the period of account.