(1) Where in any accounting period a company receives franked investment income and the amount of that income is calculated in accordance with subsection (1) (a) of section 156, the company, instead of or in addition to making a claim under section 157, may on making a claim for that purpose require that the franked investment income shall be taken into account for relief under section 396 (1) or 397 up to the amount of such income received in the accounting period which, if chargeable to corporation tax, would have been so taken into account by virtue of section 396 (6), and (subject to the restriction to the amount of franked investment income) subsections (2) to (7) shall apply where the company makes a claim under this section for any accounting period.
(2) For the purposes of the claim, the amount to which the claim relates shall be treated as trading income of the accounting period.
(a) The reduction to be made in trading income of an accounting period shall be made as f