(1)Subsections (2) and (3) apply for the purpose of calculating the amount of income received under section 797 on a chargeable event in respect of the individual and the trade.
(2)If chargeable events have previously occurred in respect of the individual and the trade, any consideration taken into account in calculating the amount of income received on an earlier chargeable event is left out of account.
(3)If chargeable events have previously occurred in respect of the individual and the trade, the amount of income received as a result of section 797(5)(b) is reduced (but not below nil) by the total amount of income received on earlier chargeable events as a result of that provision.
(4)In a case to which section 800(10) (cases in which firm is carrying on, or has carried on, more than one trade) applies—
(a)subsections (2) and (3) of this section have effect as if references to the trade were references to any of the firm's trades, and
(b)if chargeable events in respect of the individual and any of the firm's trades occur at the same time, to find the total amount of income received under section 797 at that time on those chargeable events—
(i)calculate separately the income received on each chargeable event ignoring the other chargeable events,
(ii)add the results from sub-paragraph (i) together, and
(iii)reduce the total amount of income resulting from sub-paragraph (ii) so far as necessary to ensure that no amount is included more than once in that total.