The non-resident parent's current income from self-employment is to be determined by reference to the profits of any trade, profession or vocation carried on by the non-resident parent at the effective date of the relevant calculation decision.

The profits referred to in paragraph (1) are the profits determined in accordance with Part 2 of ITTOIA for the most recently completed relevant period or, if no such period has been completed, the estimated profits for the current relevant period.

The weekly amount is calculated by dividing the amount of those profits by the number of weeks in the relevant period.

In paragraphs (2) and (3) the “relevant period” means a tax year or such other period in respect of which the non-resident parent should, in the normal course of events, report the profits or losses of the trade, profession or vocation in question to HMRC in a self-assessment return.

In the case of a non-resident parent who carries on a trade, profession or vocation in partnership, the profits referred to in this regulation are the profits attributable to the non-resident parent's share of the partnership.

The profits of a trade, profession or vocation that the non-resident parent has ceased to carry on at the effective date of the relevant calculation decision are to be taken as nil.