The amount of chargeable gains to be included in a company's total profits for an accounting period is the total amount of chargeable gains accruing to the company in the period after deducting—
any allowable losses accruing to the company in the period, and
so far as not previously deducted under this subsection, any allowable losses previously accruing to the company while it was within the charge to corporation tax.
For the purposes of corporation tax on gains "allowable loss" does not include a loss accruing to a company if, had a gain accrued, the company would not have been chargeable to corporation tax on the gain.
Subsection (4) applies if—
a company has two or more accounting periods that fall wholly within the same financial year,
the company is chargeable to corporation tax for each of those accounting periods only because of a chargeable gain accruing to the company on the disposal of asset, and
in the period (if any) between each of those accounting periods, the company is not within the charge to corporation tax.
For the purposes of determining the amount of chargeable gains to be included in the company's total profits for each of the accounting periods by reference to which this subsection applies, subsection (1) has effect as if after paragraph (a) (before the "and") there were inserted—