19.—(1) The income of a relevant person shall be determined on a weekly basis by aggregating –
(a)his average weekly earnings from employment as an employed earner, determined in accordance with this Chapter and Chapter III,
(b)his average weekly earnings from employment as a self-employed earner, determined in accordance with this Chapter and Chapter IV,
(c)his average weekly income other than earnings, determined in accordance with this Chapter and Chapter V,
(d)the weekly tariff income determined under regulation 41 (determination of tariff income from capital), and
by then deducting the average weekly relevant child care charge, determined in accordance with regulation 20 (treatment of child care charges) from the aggregated weekly income or, in a case where the conditions in paragraph (2) are met, from the aggregated weekly income plus whichever credit specified in sub-paragraph (b) of that paragraph is appropriate, up to a maximum deduction in respect of the relevant person’s family of whichever of the sums specified in paragraph (3) applies in his case.
(2) The conditions of this paragraph are that –
(a)the relevant person’s average weekly earnings as mentioned in sub-paragraph (a) or (b) of paragraph (1) are less than the lower of either of his relevant child care charges or whichever of the deductions specified in paragraph (3) otherwise applies in his case; and
(b)the relevant person or, if he is a member of a couple either the relevant person or his partner, is in receipt of either child tax credit or working tax credit.
(3) The maximum deduction for the purposes of paragraph (1) is –
(a)where the relevant person’s family includes only one child in respect of whom relevant child care charges are paid, £94·50 per week; and
(b)where the relevant person’s family includes more than one child in respect of whom relevant child care charges are paid, £140 per week.
(4) For the purposes of paragraph (1) “income” includes income to which regulations 31 (capital treated as income), 32 (notional income), 44 (determination of grant income) and 47 (treatment of student loans) refer.