(1)The rules in section 243 apply by reference to the facts known or ascertainable—
(a)at the time of the grant of the lease, or
(b)if the determination is for the purposes of section 221 (sums payable for variation or waiver of terms of lease), at the time when the contract for the variation or waiver is entered into.
(2)In applying those rules, it is assumed that all parties concerned, whatever their relationship, act as if they were at arm's length.
(3)Subsection (5) applies if—
(a)special benefits were conferred by the lease or in connection with its grant, or
(b)payments were made which one would not expect to be made by parties acting at arm's length unless such benefits had been conferred.
(4)But subsection (5) does not apply if it can be shown that the special benefits were not conferred nor the payments made for the purpose of securing—
(a)a corporation tax advantage in the application of this Chapter, or
(b)an income tax advantage in the application of Chapter 4 of Part 3 of ITTOIA 2005 (profits of property business: lease premiums etc).
(5)In applying paragraph (b) of Rule 1 in section 243, it is assumed that the special benefits would not have been conferred nor the payments made if the lease had been granted for a term ending on the date mentioned in that rule.
(6)In this section “special benefits” means benefits other than—
(a)vacant possession and beneficial occupation of the premises, or
(b)the right to receive rent at a reasonable commercial rate in respect of the premises.