Disregard the whole income and capital of HB claimants on IS, income-based JSA or income-related ESA (HB Regs Sch 5 para 4, Sch 6 para 5) #1993

Problem

housing_benefit_applicable_income adds income_support, jsa_income and esa_income to a working-age Housing Benefit claimant's income, then tapers it. In law, a claimant on one of these benefits has the whole of their income and capital disregarded, and so gets maximum HB.

Law (SI 2006/213, read on legislation.gov.uk on 2026-09-30 and 2026-10-01)

• Sch 5 para 4 (sums disregarded in the calculation of income other than earnings): "Where a claimant is on universal credit, income support, an income-based jobseeker's allowance or an income-related employment and support allowance the whole of his income."
• Sch 6 para 5 disregards, in the same case, "the whole of his capital".
• Sch 4 para 12 (earnings): "Where a claimant is on universal credit, income support, an income-based jobseeker's allowance or an income-related employment and support allowance, his earnings." Take Housing Benefit earnings disregards from net earnings only #1908 implements this one for earnings only.
• SI 2006/214 reg 5(2) sends a pension-age claimant to SI 2006/213 when the claimant or partner is on one of these benefits (SI 2006/213 reg 5(1)(b)).
• Northern Ireland: SR 2006/405 has the same structure. Check its paragraph numbers.

Scope (Enhanced FRS 2024-25, 2026, aggregates)

• About 22.4k of the 27.4k working-age HB-recipient benefit units in the model receive IS, income-based JSA or income-related ESA. In law they all get maximum HB.
• Take Housing Benefit earnings disregards from net earnings only #1908 (taking earnings disregards from earnings only) moves about 13.3k of them a further −£3.6m below the law, because the old flat disregard was partly offsetting this gap.
• Some mixed-age couples whose younger partner is on income-related ESA are also affected (see Key the Housing Benefit Guarantee Credit passport on receipt #1927).
• Working-age HB outside specified and temporary accommodation ended on 1 July 2026 in GB (Abolish working-age Housing Benefit from 1 July 2026 (NI 1 October 2026) #1910 models this), so the gap matters most for 2026-27 and earlier years, and for any continuing awards the model keeps.

Fix

Zero HB applicable income and assessable capital when the claimant or partner is in receipt of IS, income-based JSA or income-related ESA (an amount paid > 0, as in_receipt_of_guarantee_credit does for Pension Credit). Use the claimant-and-partner definition from #1896 if it has merged. Check that #1908's para 12 branch does not double count.

Then add hand-computed YAML tests, property tests, a real Enhanced FRS impact against main, and Axiom parity (extend TheAxiomFoundation/rulespec-uk#375).

Found in independent reviews of #1908 and #1927.