Regulation 34 The general rule for determining gross weekly income
The gross weekly income of a non-resident parent for the purposes of a calculation decision is a weekly amount determined at the effective date of the decision on the basis of either historic income or current income in accordance with this Chapter.
The non-resident parent’s gross weekly income is to be based on historic income unless—
current income differs from historic income by an amount that is at least 25% of historic income; or
the amount of historic income is nil or no historic income is available.
For the purposes of paragraph (2)(b) no historic income is available if HMRC did not, when a request was last made by the Secretary of State for the purposes of regulation 35, have the required information in relation to a relevant tax year.
“Relevant tax year” has the meaning given in regulation 4(2).
This regulation is subject to regulation 23(4) (change to current income outside the annual review or periodic current income check).