Charge non-dependant deductions for non-dependants within the claimant's benefit unit

[MaxGhenis]

Fixes #2014

Stacked on #2010 (base lha-bedroom-young-people), which is stacked on #2006 and #1896. Retarget to main once those merge.

Merge order

Merge this PR only together with #2007's claimant exemptions (review r2, F2).

On its own, it charges HB and national CTR deductions for adults inside the claimant's benefit unit with no claimant-side exemption: HB reg 74(6), SPC reg 55(6) and CTR Sch 1 para 8(6). Base has no such exemption either, but base never charged in-unit adults. So until #2007 lands, a blind claimant, or one receiving AA, the DLA care component, the PIP daily living component or AFIP, would newly lose HB and CTR for an adult son. UC is safe on its own, because this PR adds the UC renter exemption (Sch 4 para 15).

This PR stays in draft until then. Under the PE-UK merge-on-gates rule (d822), it lands when its parents (#2006, then #2010) are merged, #2007's exemptions are in its base, CI is green on its head, and an independent review approves that head. Two ways to land it:

• Apply Housing Benefit and national Council Tax Reduction non-dependant deductions as legislated #2007 merges first, then this PR is rebased onto it using the composition branch's resolution;
• or the composition branch in-unit-non-dep-deductions-on-2007 (see "Composition with Apply Housing Benefit and national Council Tax Reduction non-dependant deductions as legislated #2007") replaces this PR's head.

Problem

A benefit unit can include someone aged 16 or over who is neither the claimant or partner nor a child or young person the claimant is responsible for. Examples are an adult son, or a 19-year-old who has left education. In law that person is a non-dependant of the renter. The model treated them inconsistently:

• lha_renter_has_non_dependant already counted them.
• Give benefit-unit members aged 16 or over a bedroom in the LHA size criteria #2010 gives them a bedroom as non-dependants (UC Sch 4 para 10(1)(c)).
• No deduction was ever charged for them:
  • uc_non_dep_deductions and housing_benefit_non_dep_deductions counted only people in other families (is_non_dependant_of_household_head). The individual eligibility variables also excluded anyone in a family liable for rent.
  • council_tax_reduction_non_dep_deductions subtracted the claimant's own benefit unit.

So a lone parent on UC with a 25-year-old son paid no housing cost contribution. The same son in his own benefit unit in the same household cost the parent £96.55 a month.

The UC renter exemption (Sch 4 para 15) was also missing. When the renter or either joint renter is blind or receives AA, the middle or highest DLA care component, or the PIP daily living component, no contribution should be made for any non-dependant.

The law

Fetched from legislation.gov.uk on 2026-10-01.

• UC, Sch 4 para 9:
  • (1) "the members of a renter's extended benefit unit are— (a) the renter (or joint renters); (b) any child or qualifying young person for whom the renter or either joint renter is responsible; and (c) any person who is a non-dependant."
  • (2) "A person is a non-dependant if the person normally lives in the accommodation with the renter (or joint renters) and is none of the following— (a) a person within sub-paragraph (1)(a) or (b); … (f) a person who has already been treated as a non-dependant in relation to a claim for universal credit by another person liable to make relevant payments …; (g) a child or qualifying young person for whom no-one in the renter's extended benefit unit is responsible."
  • Para 13(1): "a deduction is to be made in respect of each non-dependant who is a member of the renter's extended benefit unit".
  • Para 15 exempts "any renter who is a single person", or "any joint renter where at least one joint renter is a person", to whom (2) applies. Joint renters are joint claimants (para 1(2)).
  • Para 16 exempts the non-dependant, including "(a) a person who is under 21 years old" and "(b) a person in receipt of state pension credit".
• HB, HB Regs 2006 / HB (SPC) Regs 2006 reg 3:
  • (1): "'non-dependant' means any person, except someone to whom paragraph (2) applies, who normally resides with a claimant or with whom a claimant normally resides".
  • (2) excludes:
    • "(a) any member of the claimant's family";
    • "(c) a child or young person … not a member of his household by virtue of regulation 21";
    • "(d) … [a person] liable with the claimant … to make payments in respect of his occupation of the dwelling";
    • "(e)(i) any person who is liable to make payments on a commercial basis to the claimant or the claimant's partner".
  • (4): "a person resides with another only if they share any accommodation except a bathroom, a lavatory or a communal area within the meaning prescribed in paragraph 8 of Schedule 1 but not if each person is separately liable to make payments in respect of his occupation of the dwelling to the landlord".
  • The family is the couple and their children and young persons. A young person is a Child Benefit qualifying young person (reg 19).
  • Reg 74 / SPC reg 55 deduct for a non-dependant "aged 18 or over". Under (5): "Where a person is a non-dependant in respect of more than one joint occupier of a dwelling … the deduction … shall be apportioned between the joint occupiers … having regard to the number of joint occupiers and the proportion of the payments in respect of the dwelling payable by each of them."
• CTR:
  • Definitions: SI 2012/2885 reg 9 (the same definition; family in reg 6); WSI 2013/3029 reg 9; SSI 2021/249 reg 8; SSI 2012/319 reg 3.
  • Reg 9(2)(e) excludes "any person who is liable to make payments on a commercial basis to the applicant or the applicant's partner".
  • Deductions are for non-dependants "aged 18 or over" (Sch 1 para 8 and equivalents).
  • Under para 8(5)(c), one who "is a non-dependant of two or more of the liable persons" is "apportioned equally between those liable persons".

Change

	Before	After
Who	only members of other families who are not liable for rent	also benefit-unit members who are neither the claimant/partner nor that scheme's child or young person: • is_benefit_unit_non_dependant_for_universal_credit: 16+, not a UC qualifying young person (para 9(1)-(2)(a), (g)); • is_benefit_unit_non_dependant_for_legacy_benefits: not a Child Benefit child or QYP (HB reg 3(2)(a), (c); CTR reg 9 etc.)
UC	the head's family bears other families' non-dependants	also the renter's own in-unit non-dependants, for any renter: head, sharer, boarder or lodger. Other families' non-dependants stay with the head's claim, since one non-dependant counts in one claim (para 9(2)(f)). New para 15 exemption, uc_non_dep_deductions_renter_exempt. The para 16 Pension Credit limb now applies only to the claimant or partner, who receive it.
HB	joint occupiers share other families' non-dependants by rent share	every non-dependant, in any family, is pooled and apportioned between the joint occupiers by rent share (reg 74(5)). That includes a joint occupier's own adult son and a boarder's or lodger's. A boarder or lodger is not a joint occupier with the householder, so it also bears its own in-unit non-dependant in full.
National CTR	household total minus the claimant's own family, times the joint-liability share	every non-dependant, in any family (a lodger's included), is pooled. The applicant's own family members (claimant, partner, children, young persons) are left out (reg 9(2)(a)), and the rest is apportioned by joint-liability share (para 8(5)). Only claiming families bear deductions.
Local CTR (5 English schemes)	other families' non-dependants	unchanged: the local aggregation is masked to other families (see below)

Joint occupiers and lodgers

A joint occupier's adult son normally resides with every joint occupier he shares accommodation with (HB reg 3(1), (4); CTR reg 9(1)). None of reg 3(2)(a)-(f) excludes him in relation to the other occupier, so he is a non-dependant of each, apportioned by reg 74(5) or para 8(5). That is how the model already treats a non-dependant in another family. So for joint occupiers (HB and CTR), and for CTR generally, the result does not depend on whether the survey codes the son in his parent's benefit unit or in his own: two YAML cases check the two codings give the same deductions. The exceptions are listed under "Not modelled".

Reg 3(2)(e)(i) and CTR reg 9(2)(e) exclude only the person liable to pay the claimant. The household extension in (e)(iii) is for the landlord's side. So a lodger's adult son who pays nothing himself is the householder's non-dependant. For HB he is also the lodger's own.

An earlier head (155766b) charged a joint occupier's own son wholly to that occupier, citing LHA Guidance Manual 2.093 example 2 and HBGM A5 5.622. Review r2 (F3) showed neither supports that:

• the LHA example is about the size criteria, and concerns a sister, who in the model is another family's non-dependant and is apportioned;
• 5.622 is conditional ("If a person is a non-dependant of only one of the joint occupiers").

2d54628 follows the text.

Local schemes

Merton, Kingston, Newham, Westminster and Oxford keep their own aggregation (_legacy.local_non_dep_deductions). The shared eligibility variable now also covers in-unit non-dependants. The local aggregation therefore masks the individual deductions to members of other families not liable for rent, so this PR leaves those schemes exactly as on base.

Without the mask, a jointly liable sharer's local claim would bear the head's son: Newham £489.84 in 2025 (review r2, F5). A YAML case pins this. The mask and the eligibility share one helper, in_other_non_liable_family. Branch local-ctr-in-unit-non-deps (follow-up chip) replaces the mask with each scheme's pooled aggregation.

Composition with #2007

in-unit-non-dep-deductions-on-2007 (head a6a8a71) is this PR's head plus #2007 at f5aae26, with the conflicts resolved. #2007's three commits since 6257277 carry over unchanged:

• review round 2: UC earned income, award payee (is_award_payee), capped UC, the LGFA disregard;
• is_claimant_or_partner for the couple;
• documentation.

#2007's own files match its head except where this PR's aggregation, eligibility and per-applicant exemption differ. One definition of claimant or partner, #1896's is_claimant_or_partner variable, replaces #2007's proxy helper.

• HB. Every family's non-dependants go through Apply Housing Benefit and national Council Tax Reduction non-dependant deductions as legislated #2007's deduction_per_family, then are pooled and apportioned by rent share:

  • one deduction for a couple, the higher (reg 74(3));
  • each other adult, in-unit ones included, separately.

  A boarder or lodger also bears its own in-unit non-dependant in full. The claimant exemption (reg 74(6)) zeroes the claim.

• CTR. Every family's amount is pooled: one deduction per couple, the higher (para 8(3)), or both for a Welsh working-age couple on UC (Sch 6 para 5(3)). The applicant's own family amount is replaced by its in-unit non-dependants, and the result is apportioned by joint-liability share.

  • The exemption is each applicant's own (para 8(6), "the applicant or his partner"): council_tax_reduction_applicant_has_non_dep_exemption, a benefit-unit variable with the same name and formula as Assess each Council Tax Reduction claim under its own family's scheme and exemption #2015's.
  • The household-level exemption it replaces looked only at the oldest adult's family. So a blind head exempted a sighted sharer, and a blind sharer exempted nothing (review r2, F1; three YAML cases).

• Joint income for the bands is the couple's only (reg 74(4), para 8(4)). Another adult is banded on their own income.

• IS / JSA(IB) / ESA(IR) / PC / UC exemptions apply to the award's claimant and partner only. A parent's Income Support does not exempt the son.

#2007's own tests pass there, including non_dependant_deduction_review_cases.yaml, and its property oracle reads is_claimant_or_partner.

Other compositions

• Give Council Tax Reduction to the household head's family, not the oldest adult's #2009 (CTR claimant = household head): its eligibility uses ~council_tax_reduction_claimant_benunit & ~benunit_is_rent_liable as the other-family term. Composing it means editing in_other_non_liable_family once; the local mask follows. That keeps Give Council Tax Reduction to the household head's family, not the oldest adult's #2009's case "A sharer with no rent to pay is a claimant, not a non-dependant" true in the local schemes too.
• Means-test the Council Tax Reduction applicant and partner, not the benefit unit's claimant #2078 (CTR means test assesses the applicant and partner, on Give Council Tax Reduction to the household head's family, not the oldest adult's #2009): there a liable household head who is not the benefit unit's claimant or partner applies alone. For CTR, a family's in-unit non-dependants must then be members aged 18 or over who are neither is_council_tax_reduction_applicant_or_partner nor a child or young person of the applicant's family. Whichever of Means-test the Council Tax Reduction applicant and partner, not the benefit unit's claimant #2078 and this PR lands second switches council_tax_reduction_individual_non_dep_deduction_eligible and council_tax_reduction_non_dep_deductions to that identity (SI 2012/2885 reg 9(1), (2)(a)); HB keeps is_claimant_or_partner. (composition note)
• Assess each Council Tax Reduction claim under its own family's scheme and exemption #2015 (per-family CTR scheme): council_tax_reduction_applicant_has_non_dep_exemption has the same name and formula on both branches. When composed, its documentation should say the model applies it in the national and the English working-age local schemes; the local schemes then stop reading the household-level exemption (review r3, R3-8).
• Count a non-dependant shared by joint tenants in each tenant's Housing Benefit size criteria #2035 (shared non-dependants in each joint tenant's HB size criteria): whichever of Count a non-dependant shared by joint tenants in each tenant's Housing Benefit size criteria #2035 and this PR lands second also counts a joint occupier's in-unit non-dependants in every other joint occupier's HB size criteria, through housing_benefit_other_occupiers. The YAML case for that: a joint tenant's son aged 17 not in education gives the other tenant 2 bedrooms. Apply each scheme's own non-dependant test to the LHA shared accommodation rate #2030's shared-rate flag follows. On this PR alone, in-unit non-dependants match base's other-family treatment: shared deductions, one family's size criteria.

Invariants (stated and tested)

Hypothesis properties are in test_benefit_unit_non_dependant_properties.py. They are derandomized, with 10 examples each, on populations of up to 5 households. The populations include sharers, lodgers, non-dependant families, adult children, qualifying young persons (including looked-after ones) and exemption flags.

1. Oracle (differential). A plain-Python calculation from the generated structure must match each family's UC, HB and CTR deductions, and who is eligible for an individual HB or CTR deduction. It decides who is whose non-dependant and computes HB rent shares itself. It reads the individual deduction amounts, CTR claim flags and joint-liability shares from the model (Give sharers, boarders and lodgers their own rent, tenure and LHA category #2006's variables, tested there). It covers:

   • who is whose non-dependant;
   • the para 9(2)(f) single claim;
   • reg 74(5) shares and joint-liability shares over every non-dependant;
   • a lodger's own non-dependant in full (HB);
   • the applicant's own family left out (CTR).

   The individual UC amount equals £93.02 × 12 exactly where the oracle says the person is a non-dependant aged 21+ and not exempt (2025, the year situation inputs apply to).

2. Conservation.

   • HB deductions are borne in full across the joint occupiers, plus once more by a lodger for its own non-dependant.
   • CTR deductions are borne by claiming families in proportion to their joint-liability shares. Give sharers, boarders and lodgers their own rent, tenure and LHA category #2006's per-person shares need not sum to one. This holds on the generator's domain (rent > 0, claimants always liable for it). With no rent, a jointly liable sharer is treated as another family's non-dependant by the eligibility proxy, a pre-existing defect that Give Council Tax Reduction to the household head's family, not the oldest adult's #2009's claimant-family test fixes.
   • Each UC contribution is borne by at most one family.

3. Exemptions.

   • A para 15-exempt family has no UC deductions.
   • No deduction is made for anyone under 21 (UC) or under 18 (HB, CTR).
   • No one in a rent-liable family is charged other than its in-unit non-dependants.

4. No-op. Where no benefit unit contains a non-dependant, every family's deductions equal the previous formulas.

5. Bedrooms (differential with Give benefit-unit members aged 16 or over a bedroom in the LHA size criteria #2010). The members classed as in-unit non-dependants are exactly the generated non-QYP members. Turning them into qualifying young persons leaves LHA_allowed_bedrooms unchanged.

On the composition branch the oracle also counts a couple once and applies HB reg 74(6) and per-applicant CTR para 8(6) exemptions. Its conservation checks hold where no claimant is exempt and are upper bounds otherwise.

Tests

• New benefit_unit_non_dependants.yaml: 28 cases. Expected amounts are the regulations' 2026-27 figures: UC £96.55 a month; HB £20.40 and £64.35 a week (the £279-£365 band).

  • UC: adult son; under 21; responsible QYP; looked-after QYP (para 9(2)(g)); renter on PIP; blind partner; a disabled child does not exempt the renter; son on AA; the family's PC; own plus other-family non-dependants; a non-dependant family's own adult; a sharer's own; housing element net of the contribution.
  • HB: part-time son; £300-a-week daughter; under 18; Child Benefit young person; joint tenants share one tenant's son by rent share, with the same result when he is coded as his own benefit unit; a lodger's son is the lodger's and the householder's.
  • CTR: own family; under 18; jointly liable applicants share one applicant's son equally; another family's adult, shared equally; a lodger's son is the householder's; non-claiming families bear nothing.
  • Local CTR (Newham): a jointly liable sharer does not bear the head's son.

• Updated uc_individual_non_dep_deduction(_eligible).yaml and housing_benefit_individual_non_dep_deduction_eligible.yaml. A lone person in a single-person household is not anyone's non-dependant, so these tests now state who the person is a non-dependant of.

• Full suites on 2d54628 (this PR) and 4cd6d26 (composition):

  • policyengine-core test policyengine_uk/tests/policy -c policyengine_uk: 1,539 passed (this PR), 1,627 passed (composition);
  • pytest policyengine_uk/tests --ignore=policyengine_uk/tests/policy: 2,051 passed and 45 skipped (this PR); 2,073 passed and 45 skipped (composition, including this PR's, Apply Housing Benefit and national Council Tax Reduction non-dependant deductions as legislated #2007's and Give sharers, boarders and lodgers their own rent, tenure and LHA category #2006's properties).

• Later commits, on this PR (now 270412d) and the composition (now 7875ee9):

  • the in_other_non_liable_family refactor, with no change in behaviour;
  • one YAML case (e72f2b8 / 3238db6). On those heads review r3 ran the full YAML: 1,540 passed (this PR) and 1,628 passed (composition);
  • documentation fixes, and two HB exemption YAML cases on the composition. On these, the family, local-authority and consumption YAML pass: 467 (this PR) and 557 (composition).
  • Apply Housing Benefit and national Council Tax Reduction non-dependant deductions as legislated #2007's three commits since 6257277, carried onto the composition (a6a8a71): family, local-authority and consumption YAML 566 passed; the four non-dependant and rent property suites 19 passed.

• Mutation check on 2d54628: an unmutated control plus 19 one-line mutations of the new logic, including dropping the pooling, the lodger rule, the own-family subtraction and the local mask. The control passes. The YAML cases kill 18 of the 19 mutants and the properties kill 17. The two survivors:

  • "own-family members not subtracted" binds only when an applicant's individual deduction is set directly as an input. e72f2b8 adds a YAML case that kills it.
  • "local mask dropped" is killed by the Newham YAML case only, because the properties have no local-scheme oracle. The local-scheme branch adds one.

  The script is mutate_v3.py in the review folder.

Impact (real microsimulation)

Released enhanced FRS 2024-25 (policyengine-uk-data 1.57.4, enhanced_frs_2024_25.h5, sha256 03fe15e4…). Base is #2010's head 49866c2; branch is 2d54628.

Runs at 2d54628 for 2025-2030 give arrays bitwise identical to the runs at 155766b, intermediate variables included. So the pooling, lodger and local-mask changes move nothing on the survey.

Each figure comes from a real run of the full model. The decomposition reruns the branch with one new variable set to False for everyone before any calculation:

• uc_non_dep_deductions_renter_exempt (para 15), for the "in-unit only" column;
• the two is_benefit_unit_non_dependant_* variables, for the composition's base.

A survey household is counted by its rent and members' ages, as in #2010. Any cell from fewer than 10 survey households is suppressed.

Who is in the group (2026).

• Under the UC test, 19k people (20 survey households) are non-dependants within a benefit unit: 10k aged 16-17 (12 survey households), 18-20 suppressed, and none aged 21 or over.
• The HB/CTR test gives the same 19k; those aged 18+ are suppressed.

So on the survey the in-unit charge changes no award in any year:

• UC exempts everyone under 21 (para 16(2)(a));
• HB and CTR deductions change in fewer than 10 survey households and no award moves.

Effects, £m a year:

Year	UC paid	of which para 15	of which in-unit	HB	CTR	Household net income	Benefit units with more UC
2025	+39.6	+39.6	0	0	0	+39.6	29k (28 survey households)
2026	+39.1	+39.1	0	0	0	+39.1	28k (27)
2027	+40.1	+40.1	0	0	0	+40.1	28k (27)
2028	+41.1	+41.1	0	0	0	+41.1	28k (27)
2029	+42.1	+42.1	0	0	0	+42.1	28k (27)
2030	+42.8	+42.8	0	0	0	+42.8	28k (26)

No family loses.

Para 15 in 2026. 318k benefit units (233 survey households) lose £467.7m of UC non-dependant deductions:

• £366.5m of it is in 249k families that do not rent, where it had no effect.
• £101.2m is in 70k renting families. Their housing costs element rises by £99.9m (69k, 98 survey households). UC paid rises by £39.1m for 28k (27 survey households); for 41k the housing element rises (£60.8m) but UC paid does not.

Poverty, 2026:

• before housing costs: unchanged;
• after housing costs: changes for people in fewer than 10 survey households (suppressed).

Composition with #2007 (rerun at 4cd6d26, 2026): the same.

• The in-unit charge changes no award.
• Para 15 adds £39.1m to UC.
• The per-applicant CTR exemption and the pooling change no array relative to 60cc39c.
• Apply Housing Benefit and national Council Tax Reduction non-dependant deductions as legislated #2007's per-couple fixes cannot bind on the survey: households receiving HB or CTR contain no adults (18+) in another family who are not that family's claimant or partner.

Intermediate variables. uc_individual_non_dep_deduction, household_benefits_individual_non_dep_deduction and council_tax_reduction_non_dep_deductions now read zero in two cases:

• for people who are nobody's non-dependant (for example, an owner-occupier head family's own adults);
• for families that do not claim CTR.

So their totals fall by tens of £bn. In the in-unit-only run every award is unchanged: the change is in what these variables report, not in any award.

Review

• Review r1 (Opus 5.5) was lost to a session limit. Its scratch counterexamples were folded in at 155766b.
• Review r2 (Opus 5.5, subfleet) reviewed 155766b and the composition at 60cc39c:
  • F1 (composition): household-level CTR applicant exemption. Fixed: per-applicant exemption.
  • F2 (this PR alone): no HB/CTR claimant exemptions until Apply Housing Benefit and national Council Tax Reduction non-dependant deductions as legislated #2007. Fixed by the merge order above.
  • F3: a joint occupier's own non-dependant was charged to that occupier alone. Fixed: pooled and apportioned, as the text says.
  • F4: a lodger's adult son was no one's non-dependant for CTR. Fixed: he is the householder's.
  • F5: local schemes charged a sharer for the head's son. Fixed: the local aggregation is masked to other families.
  • r2's run hit an account session limit before writing a verdict.
• Review r3 (Opus 5.5, subfleet) on e72f2b8 and 3238db6:
  • F1-F5: confirmed fixed. It also found the five local schemes exactly neutral on 5 councils × 45 benefit units × 3 heads.
  • R3-1: the composition's HB documentation still stated the reverted rule. Fixed.
  • R3-11: no YAML pinned HB exemptions under pooling. Two cases added to the composition.
  • R3-3 and R3-6: documentation of the in-unit benefits limitation and of the CTR other-family proxy. Fixed.
  • R3-2, R3-4, R3-7 and R3-10: disclosed under "Not modelled".
  • R3-5: merge-order enforcement. The PR stays in draft and the merge is Max's queued decision.
  • R3-9: PR body wording. Fixed here.
  • Verdict pending: r3 is still running its property-suite checks.

Not modelled / follow-ups

• Claimant/partner inference (Replace generic child and adult flags with each programme's legal definitions #1896): with no is_claimant_or_partner input, a lone parent and a son aged 20+ in one benefit unit are inferred as a couple, so the son is not a non-dependant. Presume a much younger member is a flagged parent's child at any age #2040 presumes such a member the claimant's child when the claimant is flagged is_parent. Unflagged ages-only households stay a couple deliberately (to avoid splitting real FRS couples), so household inputs should supply is_claimant_or_partner or is_parent.
• A joint occupier's or lodger's young person aged 18-19. Read literally, they are the other occupier's non-dependant, since they are not in that occupier's family. The model treats them as no one's.
• A boarder's or lodger's adult relative coded in his own benefit unit is charged to the householder only. Coded in the lodger's unit, he is charged to both, as reg 3(2)(e)(i) and (iii) give. The model cannot tell which separately coded adult is the lodger's. (The householder's own household is rightly not the lodger's non-dependant: reg 3(2)(e)(iii); UC Sch 4 para 9(2)(e).)
• An in-unit non-dependant's own benefits are not modelled (receives_benefits_in_own_right does not say which benefit). So the exemptions for a non-dependant on IS, income-based JSA or income-related ESA, or on UC with no earned income (HB reg 74(8), CTR Sch 1 para 8(8), SSI 2021/249 reg 90), never apply to them. The same son coded as his own benefit unit gets his own UC award and can be exempt. This sits inside the suppressed survey cell.
• Two in-unit non-dependants who are a couple pay two deductions on the composition branch, not one on their joint income (reg 74(3)-(4)). The model has no relationship data to pair them. The FRS gives every couple its own benefit unit, so this arises only in user-entered households.
• UC "one claim" (para 9(2)(f)). Other families' non-dependants go to the household head's claim, and a family's own to its own claim, whether or not that family claims UC. If the assigned family makes no UC claim, (f) does not apply and another renter's claim should bear them.
• Inherited from Give sharers, boarders and lodgers their own rent, tenure and LHA category #2006:
  • per-person joint-liability shares, so for a couple jointly liable with a single sharer, part of each pooled CTR deduction is charged to no one;
  • FRS sharers with their own agreement are apportioned as joint occupiers, although reg 3(4)'s tail and reg 74(5) would charge each claim in full.
• Para 16(2)(i), a non-dependant responsible for a child under 5, is not modelled for anyone; nor are (ca)/(da)/(ea), (f), (h) and (j), and para 15's Scottish limbs. Follow-up filed.
• Local English CTR schemes: branch local-ctr-in-unit-non-deps (follow-up).

axiom:

• UC Sch 4 para 13: encoded-correct. uk/regulations/uksi/2013/376/schedule/4/paragraph/13.yaml, companion housing_cost_contribution_required_for_qualifying_non_dependant: a non-dependant who is a member of the extended benefit unit requires a contribution, whichever family they are in.
• UC Sch 4 paras 15-16: Encode UC Sch 4 paras 15 and 16 (housing cost contribution exemptions) and wire them into para 13 (PE parity: policyengine-uk#2014) TheAxiomFoundation/rulespec-uk#413, queued. Neither the module nor the corpus rows exist.
• UC Sch 4 para 9, HB reg 3 and CTR reg 9 (the in-unit non-dependant judgment, joint occupiers and lodgers): Encode the payer side for sharers, boarders and lodgers: UC Sch 4 paras 9 and 20, HB regs 3, 12B, 13D, 74 and Sch 1 meals, CTR joint liability (PE parity: policyengine-uk#2006) TheAxiomFoundation/rulespec-uk#406, queued. Step 1 plus the in-unit addendum and its second correction, which restores apportionment and adds the lodger rule.
• HB reg 74 / SPC reg 55 and CTR Sch 1 para 8 (couple-only rule, own-award exemptions): Encode non-dependant deductions: HB Regs 2006 reg 74 and HB (SPC) reg 55 conditions and exemptions; CTR SI 2012/2885 Sch 1 para 8, WSI 2013/3029 Sch 1 para 3 and Sch 6 para 5, SSI 2012/319 reg 48, SSI 2021/249 reg 90 (PE parity: policyengine-uk#2007) TheAxiomFoundation/rulespec-uk#407, queued (addendum).

🤖 Generated with Claude Code

[MaxGhenis]

Composition note from #2078 (stacked on #2009), which makes the CTR means test assess the applicant and partner rather than the benefit unit's claimant and partner.

#2078 adds is_council_tax_reduction_applicant_or_partner (Person) and council_tax_reduction_head_applies_alone (BenUnit). Where the household head is liable but is not the benefit unit's claimant or partner, the head applies alone, and the benefit unit's claimant and partner are not her family. An example is a grandmother head sharing a benefit unit with a young couple and their baby.

For CTR, a family's in-unit non-dependants should then be benefit-unit members aged 18 or over who are neither is_council_tax_reduction_applicant_or_partner nor a child or young person of the applicant's family. Here is_benefit_unit_non_dependant_for_legacy_benefits uses is_claimant_or_partner. Composed with #2009/#2078, that would make the grandmother a non-dependant in her own claim and the young couple not hers, the reverse of the law (SI 2012/2885 reg 9(1), (2)(a)). HB can keep the generic identity; the CTR deduction (council_tax_reduction_individual_non_dep_deduction_eligible, council_tax_reduction_non_dep_deductions) needs the CTR one.

This matters more after #2078: for a head who applies alone, #2078 stops counting the young couple's income, as the law requires, and leaves their non-dependant deduction (when they are 18 or over) to this PR.