§ 6. "That, for the purposes of the proviso to subsection (1) of section twenty-four of the Finance Act, 1920, the relief provided for by 1223 section twenty-seven of that Act shall be left out of the account in computing—
- (a) the amount of the income tax payable by an individual; and
- (b) the amount which would be payable by him by way of income tax if the tax were chargeable on his total income from ail sources, including income which is not subject to income tax charged in the United Kingdom.