9Where, in the case of any dividend, foreign income tax not chargeable directly or by deduction in respect of the dividend is, under the arrangements, to be taken into account in considering whether any, and if so what, credit is to be given against income tax in respect of the dividend, the foreign income tax not so chargeable which is to be taken into account shall be that borne by the body corporate paying the dividend upon the relevant profits insofar as it is properly attributable to the proportion of the relevant profits which is represented by the dividend.
The relevant profits are—
(a)if the dividend is paid for a specified period, the profits of that period ;
(b)if the dividend is not paid for a specified period but is paid out of specified profits, those profits ;
(c)if the dividend is paid neither for a specified period nor out of specified profits, the profits of the last period for which accounts of the body corporate were made up which ended before the dividend became payable :
Provided that if, in a case falling under sub-paragraph (a) or sub-paragraph (c) of this paragraph, the total dividend exceeds the profits available for distribution of the period mentioned in the said sub-paragraph (a) or the said sub-paragraph (c), as the case may be, the relevant profits shall be the profits of that period plus so much of the profits available for distribution of preceding periods (other than profits previously distributed or previously treated as relevant for the purposes of this paragraph) as is equal to the excess ; and for the purposes of this proviso the profits of the most recent preceding period shall first be taken into account, then the profits of the next most recent preceding period, and so on.