(1)For the purposes of sections 792 and 793 a “post-1 December 2004 loss” means—
(a)any loss made by an individual in a trade in a tax year the basis period for which begins on or after 2 December 2004, or
(b)the post-1 December 2004 part of any loss made by an individual in a trade in a tax year the basis period for which includes 2 December 2004 (but begins before that date).
(2)The “post-1 December 2004 part” of any loss made by an individual in a trade means the individual's share of any losses made by the relevant firm in the trade in the period—
(a)beginning with 2 December 2004, and
(b)ending with the end of the basis period for the tax year concerned.
(3)For this purpose “the relevant firm” means the firm in which the individual carried on the trade, and—
(a)the losses of that firm are calculated as if that period were one for which profits and losses had to be calculated for the purposes of section 849 of ITTOIA 2005 (calculation of firm's profits or losses), and
(b)the individual's share of the losses is determined in accordance with the individual's interest in the firm during that period.
(4)In this section “basis period”, in relation to an individual with a notional trade, means the basis period for the notional trade (within the meaning of Part 9 of ITTOIA 2005).