M1In accordance with sections 6 to 12 and 337 to 344, for the purposes of corporation tax for any accounting period income shall be computed under Cases I to VI of Schedule D on the full amount of the profits or gains or income arising in the period (whether or not received in or transmitted to the United Kingdom), without any other deduction than is authorised by the Corporation Tax Acts.

M2Where a company is chargeable to corporation tax in respect of a trade or vocation under Case V of Schedule D, the income from the trade or vocation shall be computed in accordance with the rules applicable to Case I of Schedule D.

M3Cases IV and V of Schedule D shall for the purposes of corporation tax extend to companies not resident in the United Kingdom, so far as those companies are chargeable to tax on income of descriptions which, in the case of companies resident in the United Kingdom, fall within those Cases (but without prejudice to any provision of the Tax Acts specially exempting non-residents from tax on any particular description of income).