31.—Capital gains tax shall be charged on the total amount of chargeable gains accruing to the person chargeable in the year of assessment, after deducting-

( a ) any allowable losses accruing to that person in that year of assessment, and

( b ) in so far as they have not been allowed as a deduction from chargeable gains accruing in any previous year of assessment, any allowable losses accruing to that person in any previous year of assessment (not earlier than the year 1974-75).

INCOME TAX AND CORPORATION TAX: THE MAIN PROVISIONS