[juaristi22]

Refs #2410

Advance repayment demand currently rises with the Universal Credit standard allowance. For a single claimant aged 30 in 2025, a legacy 10% advance represents £40.014/month at the unreformed £400.14 allowance. Raising the allowance to £440 makes the old demand £44. This change keeps demand at £40.014, subject to the existing cap and available award.

uc_advance_repayment_amount is intended to accept known annual cash repayments, including explicit zero; the current draft has the mixed-unit limitation described below. Its fallback retains the existing type-share estimate and uses the same year's unreformed allowance. The existing deduction-rate input, abolition switches, cap, penny floor and protected-floor allocation retain their behavior. SI 2013/383 reg. 10 provides for cash advance recovery. Recovery can still rise when a higher allowance releases a binding cap.

This fixes allowance reform responses within an annual cross-section. Cohort repayments across years, family-status changes, maintenance priority and coarse non-advance estimates remain unresolved under #2410; no maintenance or last-resort interface is added.

Validation:

• 33 affected YAML cases and 26 Python tests pass, with no skips. Includes both existing supplied-rate regression variants with unchanged expectations, the dated reform route, binding caps, explicit zero, abolition and an actual-input synthetic capped family.
• In the London couple with four children and £30,000 council rent, a £600 annual advance leaves the same £20,677.40 payment before and after a 10% allowance uplift.
• Ruff format/check on all four changed Python files and whitespace checks pass. Tests used an existing Python 3.13 environment with checkout imports and external caches; full population validation and documentation build were not run locally.
• Historical review record, 22 October: this chat's final independent code and policy review reported COMPLETE/APPROVE at 41daefdd1671b029b8c2c650d30787f586cdd69f, resolving its C1, C2 and A1 findings. That result predates the hub's mixed-unit finding and is not a current no-open-findings assessment.
• Current draft status: the mixed-unit missingness P2 remains open at 41daefdd1671b029b8c2c650d30787f586cdd69f. Supplying a cash repayment, including zero, for one benefit unit can suppress the fallback for other unsupplied units. Hub PR Preserve missing UC advance repayments in mixed populations #2581 at 52201202239dfb73ddb5224ceff0753cdc2e4787 contains the proposed repair and has not been adopted here.
• This chat recorded 99 focused passes on 22 October on the separate Preserve missing UC advance repayments in mixed populations #2581 head 52201202239dfb73ddb5224ceff0753cdc2e4787 (81 Python items and 18 YAML cases). Max's 23 October comment6357230112 separately attests approval at that stacked head. These are distinct from the full canonical report, result JSON and workflow provenance, which are still awaited following the once-posted packet request.
• Vahid's round-one comment confirms the current draft finding and states that he did not read the complete Preserve missing UC advance repayments in mixed populations #2581 diff. It does not complete the missing packet. Historical CI and other reviewers' execution claims are not new current-main validation by this chat.

Reproducer: policyengine_uk/tests/policy/baseline/finance/benefit/family/universal_credit/uc_fixed_deductions.yaml::A legacy advance rate uses the same year's unreformed allowance

axiom: TheAxiomFoundation/rulespec-uk#486 queued (cash advance recovery; signed encoder blocked pending separate per-run approval)

[github-actions]

Aggregate impact on certified data: pass

Base fe0b99a36b against head 4f4dcfb65e, both on enhanced_frs_2024_25.h5 (policyengine-uk-data 1.58.1, sha256 056e80fd8e91), fiscal years 2025-26 to 2031-32. Each year is a full microsimulation run on each side.

Checks: 0 broken by this change, 1 failing on both sides, 0 fixed. Moves flagged for review: 0 (thresholds in report_spec.yaml; a flag does not fail the job).

Workflow run and full report

Notes

• In the years a figure from fewer than 10 records is suppressed (spending.disabled_students_allowance), every total containing it, and the decile incomes, are rebuilt from their other components, so no published total includes it. Those totals are marked †. A change is withheld where the two sides leave out different figures and can't be lined up.

Moves flagged for review

None.

Spending by benefit and service

Measure	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Universal Credit	+£2	-£11	+£12	+£8	-£5	+£0	+£1
Disabled Students' Allowance	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed

Caseloads

Measure	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Disabled Students' Allowance	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed

Government balance, each component counted once

Measure	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Government spending	+£2 †	-£11 †	+£12 †	+£8 †	-£5 †	+£0 †	+£1 †
Government balance, each receipt once	-£2 †	+£11 †	-£12 †	-£8 †	+£5 †	-£0 †	-£1 †

Model totals

Measure	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
gov_spending	+£2 †	-£11 †	+£12 †	+£8 †	-£5 †	+£0 †	+£1 †
household_benefits	+£2 †	-£11 †	+£12 †	+£8 †	-£5 †	+£0 †	+£1 †
gov_balance	-£2 †	+£11 †	-£12 †	-£8 †	+£5 †	-£0 †	-£1 †

Household income totals

Measure	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Household net income	+£2 †	-£11 †	+£12 †	+£8 †	-£5 †	+£0 †	+£1 †
Household net income (HBAI definition)	0	0	+£21	+£7	-£0	0	+£1

Inequality

Measure	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Gini coefficient, equivalised HBAI income before housing costs	0	0	-0.0000	-0.0000	+0.0000	0	-0.0000

Mean household net income in each side's own deciles

Measure	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Decile 1: mean household_net_income per household	0 †	+£0.00 †	+£0.00 †	+£0.00 †	-£0.00 †	+£0.00 †	+£0.00 †
Decile 2: mean household_net_income per household	+£0.00 †	+£0.00 †	+£0.00 †	+£0.00 †	-£0.00 †	-£0.00 †	+£0.00 †
Decile 3: mean household_net_income per household	+£0.00 †	0 †	+£0.00 †	+£0.00 †	-£0.00 †	+£0.00 †	+£0.00 †
Decile 4: mean household_net_income per household	+£0.00 †	0 †	+£0.00 †	+£0.00 †	0 †	0 †	+£0.00 †
Decile 5: mean household_net_income per household	0 †	-£0.00 †	+£0.00 †	+£0.00 †	-£0.00 †	+£0.00 †	+£0.00 †
Decile 6: mean household_net_income per household	0 †	0 †	+£0.00 †	+£0.00 †	0 †	0 †	0 †
Decile 7: mean household_net_income per household	0 †	0 †	+£0.00 †	+£0.00 †	-£0.00 †	0 †	+£0.00 †
Decile 8: mean household_net_income per household	0 †	0 †	0 †	0 †	-£0.00 †	0 †	0 †
Decile 9: mean household_net_income per household	0 †	0 †	0 †	0 †	0 †	0 †	+£0.00 †
Decile 10: mean household_net_income per household	0 †	0 †	0 †	+£0.00 †	0 †	0 †	0 †

Standard reform costings (change in gov_balance)

Measure	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Raise basic rate by 1pp	+£0	0	+£0	+£0	+£0	0	-£0
Raise higher rate by 1pp	0	0	0	+£0	0	0	0
Raise personal allowance by ~800GBP/year	+£0	0	+£12	+£0	-£0	0	-£0
Raise child benefit by 25GBP/week per additional child	0	0	+£20	+£0	0	0	+£0
Reduce Universal Credit taper rate to 20%	+£2	+£26	+£12	+£21	+£0	-£1	-£1
Raise Class 1 main employee NICs rate to 10%	+£0	0	+£0	+£0	0	-£0	-£0
Raise VAT standard rate by 2pp	+£0	0	-£0	0	-£0	-£0	+£0
Raise additional rate by 3pp	0	0	+£0	0	0	0	0
Raise the Universal Credit standard allowance by 10%	-£30.8m	-£32.9m	-£33.9m	-£35.0m	-£35.8m	-£36.7m	-£37.5m
Raise the State Pension by 10%	+£0	0	-£0	0	0	0	+£0

Standard reforms: change in each reform's target

Measure	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Reduce Universal Credit taper rate to 20%: change in universal_credit	-£2	-£12	+£4	-£12	-£1	+£0	+£1
Raise the Universal Credit standard allowance by 10%: change in universal_credit	+£30.8m	+£32.9m	+£33.9m	+£35.0m	+£35.8m	+£36.7m	+£37.5m

Household net income by decile

No household's net income changes in any year.

No change in any year: receipts by tax head; population; poverty rates; people in poverty.

Checks failing on both base and head (1)

• VAT is never negative (sign:vat): 2025-26: 76 units below zero, a weighted £-54,797,972 in total; 2026-27: 76 units below zero, a weighted £-56,271,349 in total; 2027-28: 76 units below zero, a weighted £-57,609,146 in total

Counted-once check

Each of 84 components was raised by £1 per unit in 2026-27, and every head of its totals was read household by household: its own head must rise by exactly £1, no other tax head may move, no other benefit may rise, and the model's own total must move by what its heads moved. A head that breaks a rule is measured again twice: with every other head held at its baseline value, and with every other head held at its value after the first £1 while the component rises again. It fails where either still shows the response. 0 failed; 0 were skipped.

Provenance

Side	Commit	Runtime	Environment hash	Partition hash	Time
base	main fe0b99a36b	uk 2.147.2 (files 16352cfe8445), core 3.33.2, py 3.13.17 aarch64	5c9a49667c9b	d4c1e9f08160	1594.07s
head	#2574 merged into main 4f4dcfb65e	uk 2.147.2 (files d560c8ec0c63), core 3.33.2, py 3.13.17 aarch64	5c9a49667c9b	d4c1e9f08160	1581.71s

Dataset: hf://policyengine/policyengine-uk-data-private/enhanced_frs_2024_25.h5@2526edbbb687a3b54dbb11272e5389e4b62d2ac2, sha256 056e80fd8e9151d78f432a25cde863340baee81304c6216a37fb575ce8563784 (verified on both sides), policyengine-uk-data 1.58.1.

Receipts by tax head: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Income tax	£299.29bn	£319.01bn	£336.47bn	£351.62bn	£367.17bn	£385.29bn	£403.59bn
National Insurance (employee and self-employed)	£52.58bn	£54.94bn	£56.75bn	£58.48bn	£60.62bn	£62.57bn	£65.03bn
National Insurance (employer)	£152.64bn	£159.18bn	£164.14bn	£168.73bn	£176.11bn	£181.72bn	£188.90bn
Employer NI change borne by capital	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Employer NI change borne by consumers	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Capital gains tax	£12.62bn	£13.06bn	£13.55bn	£14.04bn	£14.54bn	£15.09bn	£15.65bn
Student loan repayments	£7.83bn	£8.12bn	£8.35bn	£8.56bn	£8.79bn	£9.04bn	£9.38bn
VAT	£253.71bn	£260.53bn	£266.72bn	£273.14bn	£279.83bn	£286.71bn	£293.71bn
Change in VAT from its baseline	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
VAT on private school fees	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Fuel duties	£24.53bn	£24.64bn	£26.64bn	£26.69bn	£26.42bn	£25.76bn	£26.35bn
Alcohol duties	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Tobacco duties	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Vehicle excise duties	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
TV licence fee	£4.28bn	£4.43bn	£4.44bn	£4.46bn	£4.48bn	£4.51bn	£4.53bn
Council tax	£49.56bn	£52.45bn	£55.78bn	£59.39bn	£62.98bn	£66.74bn	£70.70bn
High value council tax surcharge	£0.00bn	£0.00bn	£0.00bn	£0.48bn	£0.49bn	£0.51bn	£0.52bn
Northern Ireland domestic rates	£0.55bn	£0.58bn	£0.61bn	£0.63bn	£0.67bn	£0.70bn	£0.73bn
Business rates	£31.73bn	£31.73bn	£31.73bn	£31.73bn	£31.73bn	£31.73bn	£31.73bn
Stamp duty land tax on the household's own purchases	£6.93bn	£7.42bn	£7.85bn	£8.26bn	£8.68bn	£9.09bn	£9.51bn
Stamp duty land tax paid by companies	£3.13bn	£3.13bn	£3.13bn	£3.13bn	£3.13bn	£3.13bn	£3.13bn
Land transaction tax (Wales)	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Land and buildings transaction tax (Scotland)	£0.01bn	£0.01bn	£0.02bn	£0.02bn	£0.02bn	£0.02bn	£0.02bn
Unspecified tax change borne by capital	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Unspecified tax change borne by consumers	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Wealth tax	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Wealth tax excluding the main residence	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Land value tax	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Carbon tax	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn

Spending by benefit and service: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
State Pension	£122.15bn	£126.64bn	£127.57bn	£129.47bn	£133.29bn	£137.24bn	£141.32bn
Pension Credit	£6.68bn	£7.07bn	£7.06bn	£7.13bn	£7.26bn	£7.39bn	£7.49bn
Winter Fuel Payment	£1.70bn	£1.68bn	£1.59bn	£1.58bn	£1.57bn	£1.55bn	£1.52bn
Pension Age Winter Heating Payment (Scotland)	£0.19bn	£0.20bn	£0.20bn	£0.21bn	£0.21bn	£0.22bn	£0.22bn
Universal Credit	£75.54bn	£80.75bn	£82.55bn	£84.28bn	£85.26bn	£86.64bn	£87.92bn
Housing Benefit	£8.59bn	£8.93bn	£9.19bn	£9.34bn	£9.61bn	£9.87bn	£10.15bn
Council Tax Reduction	£1.99bn	£2.03bn	£2.08bn	£2.13bn	£2.18bn	£2.23bn	£2.29bn
Employment and Support Allowance (income-related)	£2.12bn	£2.18bn	£2.23bn	£2.28bn	£2.33bn	£2.39bn	£2.45bn
Employment and Support Allowance (contribution-based)	£5.22bn	£5.36bn	£5.49bn	£5.62bn	£5.76bn	£5.90bn	£6.04bn
Jobseeker's Allowance (income-based)	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Jobseeker's Allowance (contribution-based)	£0.29bn	£0.30bn	£0.30bn	£0.31bn	£0.32bn	£0.33bn	£0.33bn
Income Support	£0.12bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Working Tax Credit	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Child Tax Credit	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Incapacity Benefit	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Personal Independence Payment	£27.05bn	£28.19bn	£28.94bn	£29.64bn	£30.37bn	£31.11bn	£31.87bn
Disability Living Allowance	£7.52bn	£7.83bn	£8.04bn	£8.24bn	£8.44bn	£8.65bn	£8.86bn
Attendance Allowance	£8.71bn	£9.08bn	£9.32bn	£9.55bn	£9.78bn	£10.02bn	£10.26bn
Carer's Allowance	£4.50bn	£4.69bn	£4.81bn	£4.93bn	£5.05bn	£5.17bn	£5.29bn
Carer Support Payment (Scotland)	£0.31bn	£0.32bn	£0.33bn	£0.34bn	£0.35bn	£0.36bn	£0.36bn
Carer's Allowance Supplement (Scotland)	£0.00bn	£0.04bn	£0.04bn	£0.04bn	£0.04bn	£0.04bn	£0.04bn
Severe Disablement Allowance	£0.03bn	£0.03bn	£0.03bn	£0.03bn	£0.03bn	£0.03bn	£0.03bn
Industrial Injuries Disablement Benefit	£0.51bn	£0.52bn	£0.53bn	£0.54bn	£0.56bn	£0.57bn	£0.59bn
Armed Forces Compensation Scheme	£0.61bn	£0.62bn	£0.64bn	£0.65bn	£0.67bn	£0.69bn	£0.70bn
War Widow's or Widower's Pension	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Child Benefit	£16.23bn	£16.91bn	£17.32bn	£17.73bn	£18.16bn	£18.60bn	£19.04bn
Scottish Child Payment	£0.50bn	£0.52bn	£0.53bn	£0.55bn	£0.56bn	£0.57bn	£0.58bn
Two Child Limit Payment (Scotland, counterfactual)	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Healthy Start vouchers	£0.05bn	£0.05bn	£0.05bn	£0.05bn	£0.05bn	£0.05bn	£0.05bn
Maternity Allowance	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Statutory Maternity Pay	£3.32bn	£3.41bn	£3.49bn	£3.57bn	£3.66bn	£3.75bn	£3.84bn
Statutory Paternity Pay	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Statutory Sick Pay	£1.13bn	£1.16bn	£1.19bn	£1.22bn	£1.25bn	£1.28bn	£1.31bn
Sure Start Maternity Grant	£0.01bn	£0.01bn	£0.01bn	£0.01bn	£0.01bn	£0.01bn	£0.01bn
Bereavement Support Payment	£0.67bn	£0.69bn	£0.70bn	£0.72bn	£0.74bn	£0.76bn	£0.78bn
Tax-Free Childcare	£0.55bn	£0.56bn	£0.57bn	£0.58bn	£0.60bn	£0.61bn	£0.59bn
Extended childcare entitlement	£2.69bn	£3.18bn	£3.26bn	£3.33bn	£3.42bn	£3.51bn	£3.60bn
Universal childcare entitlement	£2.26bn	£2.45bn	£2.51bn	£2.58bn	£2.64bn	£2.72bn	£2.78bn
Targeted childcare entitlement	£0.57bn	£0.60bn	£0.62bn	£0.63bn	£0.65bn	£0.66bn	£0.67bn
Care to Learn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Childcare Grant	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Parents' Learning Allowance	£0.20bn	£0.20bn	£0.20bn	£0.20bn	£0.20bn	£0.20bn	£0.20bn
Adult Dependants' Grant	£0.06bn	£0.06bn	£0.04bn	£0.04bn	£0.04bn	£0.04bn	£0.04bn
Travel Grant	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Disabled Students' Allowance	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed
16 to 19 Bursary Fund	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
NHS spending	£204.68bn	£205.46bn	£206.22bn	£207.04bn	£207.96bn	£208.89bn	£209.79bn
State education spending	£0.02bn	£0.02bn	£0.02bn	£0.02bn	£0.02bn	£0.02bn	£0.02bn
Transport subsidy spending	£25.15bn	£25.25bn	£25.34bn	£25.44bn	£25.55bn	£25.67bn	£25.78bn
Cost-of-living support payment	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Energy Bills Rebate	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Energy Price Guarantee subsidy	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Basic income	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Disability basic income	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Other public spending budget change	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn

Caseloads: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
State Pension	11,308k	11,208k	10,906k	10,812k	10,860k	10,908k	10,955k
Pension Credit	1,491k	1,489k	1,478k	1,459k	1,459k	1,457k	1,453k
Winter Fuel Payment	7,091k	7,011k	6,601k	6,517k	6,493k	6,381k	6,254k
Pension Age Winter Heating Payment (Scotland)	806k	807k	807k	805k	809k	812k	816k
Universal Credit	6,361k	6,370k	6,402k	6,412k	6,386k	6,378k	6,363k
Housing Benefit	1,254k	1,252k	1,254k	1,240k	1,245k	1,247k	1,249k
Council Tax Reduction	3,186k	3,211k	3,224k	3,245k	3,264k	3,280k	3,293k
Employment and Support Allowance (income-related)	187k	188k	188k	189k	190k	190k	191k
Employment and Support Allowance (contribution-based)	722k	724k	727k	730k	733k	737k	740k
Jobseeker's Allowance (income-based)	0k	0k	0k	0k	0k	0k	0k
Jobseeker's Allowance (contribution-based)	67k	67k	68k	68k	68k	69k	69k
Income Support	25k	0k	0k	0k	0k	0k	0k
Working Tax Credit	0k	0k	0k	0k	0k	0k	0k
Child Tax Credit	0k	0k	0k	0k	0k	0k	0k
Incapacity Benefit	0k	0k	0k	0k	0k	0k	0k
Personal Independence Payment	3,581k	3,595k	3,608k	3,623k	3,639k	3,655k	3,671k
Disability Living Allowance	1,296k	1,301k	1,306k	1,311k	1,317k	1,323k	1,329k
Attendance Allowance	1,701k	1,708k	1,714k	1,721k	1,729k	1,736k	1,744k
Carer's Allowance	1,038k	1,042k	1,046k	1,050k	1,055k	1,059k	1,064k
Carer Support Payment (Scotland)	71k	72k	72k	72k	73k	73k	73k
Carer's Allowance Supplement (Scotland)	0k	72k	72k	72k	73k	73k	73k
Severe Disablement Allowance	4k	4k	4k	4k	4k	4k	4k
Industrial Injuries Disablement Benefit	137k	138k	139k	139k	140k	140k	141k
Armed Forces Compensation Scheme	94k	94k	94k	95k	95k	95k	96k
War Widow's or Widower's Pension	0k	0k	0k	0k	0k	0k	0k
Child Benefit	8,136k	8,165k	8,185k	8,215k	8,249k	8,282k	8,314k
Scottish Child Payment	352k	354k	355k	356k	357k	358k	357k
Two Child Limit Payment (Scotland, counterfactual)	0k	0k	0k	0k	0k	0k	0k
Healthy Start vouchers	200k	201k	202k	203k	204k	204k	205k
Maternity Allowance	0k	0k	0k	0k	0k	0k	0k
Statutory Maternity Pay	334k	335k	336k	338k	339k	341k	342k
Statutory Paternity Pay	0k	0k	0k	0k	0k	0k	0k
Statutory Sick Pay	182k	183k	183k	184k	185k	186k	186k
Sure Start Maternity Grant	26k	26k	26k	27k	27k	27k	27k
Bereavement Support Payment	98k	98k	99k	99k	100k	100k	101k
Tax-Free Childcare	1,018k	1,029k	1,029k	1,033k	1,035k	1,039k	1,024k
Extended childcare entitlement	718k	724k	728k	732k	737k	741k	743k
Universal childcare entitlement	986k	989k	992k	997k	1,002k	1,013k	1,015k
Targeted childcare entitlement	119k	120k	120k	121k	121k	122k	121k
Care to Learn	0k	0k	0k	0k	0k	0k	0k
Childcare Grant	0k	0k	0k	0k	0k	0k	0k
Parents' Learning Allowance	98k	99k	99k	100k	100k	100k	101k
Adult Dependants' Grant	18k	18k	12k	13k	13k	13k	13k
Travel Grant	0k	0k	0k	0k	0k	0k	0k
Disabled Students' Allowance	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed
16 to 19 Bursary Fund	0k	0k	0k	0k	0k	0k	0k
Cost-of-living support payment	0k	0k	0k	0k	0k	0k	0k
Energy Bills Rebate	0k	0k	0k	0k	0k	0k	0k
Energy Price Guarantee subsidy	0k	0k	0k	0k	0k	0k	0k
Basic income	0k	0k	0k	0k	0k	0k	0k
Disability basic income	0k	0k	0k	0k	0k	0k	0k

Government balance, each component counted once: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Government receipts, each component once	£899.38bn	£939.24bn	£976.18bn	£1,009.38bn	£1,045.66bn	£1,082.60bn	£1,123.48bn
Government spending	£531.94bn †	£546.98bn †	£553.05bn †	£560.03bn †	£568.60bn †	£577.76bn †	£586.86bn †
Government balance, each receipt once	£367.45bn †	£392.26bn †	£423.13bn †	£449.35bn †	£477.06bn †	£504.85bn †	£536.62bn †
Benefits in household_benefits but not in gov_spending	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn

Model totals: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
gov_tax	£899.38bn	£939.24bn	£976.18bn	£1,009.38bn	£1,045.66bn	£1,082.60bn	£1,123.48bn
household_tax	£493.03bn	£519.53bn	£545.32bn	£567.51bn	£589.72bn	£614.17bn	£640.87bn
pre_budget_change_household_tax	£485.21bn	£511.41bn	£536.97bn	£558.47bn	£580.44bn	£604.62bn	£630.98bn
gov_spending	£531.94bn †	£546.98bn †	£553.05bn †	£560.03bn †	£568.60bn †	£577.76bn †	£586.86bn †
household_benefits	£531.94bn †	£546.98bn †	£553.05bn †	£560.03bn †	£568.60bn †	£577.76bn †	£586.86bn †
gov_balance	£367.45bn †	£392.26bn †	£423.13bn †	£449.35bn †	£477.06bn †	£504.85bn †	£536.62bn †

Household income totals: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Household market income	£1,657.06bn	£1,719.25bn	£1,771.68bn	£1,821.99bn	£1,872.88bn	£1,930.99bn	£2,001.98bn
Household net income	£1,656.69bn †	£1,705.94bn †	£1,737.53bn †	£1,771.57bn †	£1,807.68bn †	£1,849.24bn †	£1,900.92bn †
Household net income (HBAI definition)	£1,463.15bn	£1,510.70bn	£1,542.73bn	£1,575.67bn	£1,609.74bn	£1,648.74bn	£1,699.14bn

Population: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
People	69,514k	69,778k	70,036k	70,316k	70,626k	70,944k	71,249k
Benefit units	35,247k	35,381k	35,512k	35,654k	35,811k	35,972k	36,127k
Households	31,167k	31,285k	31,401k	31,526k	31,665k	31,808k	31,944k

Poverty rates: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Absolute poverty, before housing costs: everyone	16.2%	15.2%	15.7%	15.8%	15.9%	16.0%	15.9%
Absolute poverty, before housing costs: children	24.6%	21.4%	22.0%	21.9%	22.1%	22.3%	22.2%
Absolute poverty, before housing costs: working-age adults	13.9%	13.5%	14.1%	14.2%	14.3%	14.4%	14.4%
Absolute poverty, before housing costs: pensioners	13.7%	13.2%	13.3%	13.5%	13.6%	13.7%	13.7%
Absolute poverty, after housing costs: everyone	21.5%	20.8%	21.5%	21.8%	22.2%	22.4%	22.5%
Absolute poverty, after housing costs: children	33.4%	30.9%	31.6%	31.8%	32.4%	32.9%	33.2%
Absolute poverty, after housing costs: working-age adults	19.8%	19.6%	20.4%	20.6%	20.9%	21.2%	21.2%
Absolute poverty, after housing costs: pensioners	12.8%	12.6%	12.6%	13.1%	13.4%	13.4%	13.4%
Relative poverty, before housing costs: everyone	17.2%	16.5%	16.6%	16.6%	16.4%	16.5%	16.7%
Relative poverty, before housing costs: children	26.4%	23.7%	23.7%	23.6%	23.2%	23.3%	23.5%
Relative poverty, before housing costs: working-age adults	14.6%	14.4%	14.7%	14.8%	14.7%	14.8%	14.9%
Relative poverty, before housing costs: pensioners	15.0%	14.8%	14.4%	14.3%	14.0%	14.0%	14.4%
Relative poverty, after housing costs: everyone	21.7%	21.1%	21.4%	21.4%	21.5%	21.6%	22.0%
Relative poverty, after housing costs: children	33.5%	31.3%	31.4%	31.3%	31.3%	31.5%	32.1%
Relative poverty, after housing costs: working-age adults	19.9%	19.8%	20.2%	20.4%	20.5%	20.6%	20.9%
Relative poverty, after housing costs: pensioners	13.0%	12.7%	12.6%	12.3%	12.2%	12.2%	12.9%

People in poverty: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Absolute poverty, before housing costs: everyone	11,270k	10,578k	10,975k	11,077k	11,210k	11,339k	11,354k
Absolute poverty, before housing costs: children	3,696k	3,227k	3,332k	3,325k	3,371k	3,407k	3,408k
Absolute poverty, before housing costs: working-age adults	5,940k	5,792k	6,115k	6,209k	6,281k	6,360k	6,367k
Absolute poverty, before housing costs: pensioners	1,634k	1,559k	1,527k	1,543k	1,558k	1,572k	1,579k
Absolute poverty, after housing costs: everyone	14,972k	14,539k	15,080k	15,313k	15,657k	15,918k	16,049k
Absolute poverty, after housing costs: children	5,005k	4,656k	4,776k	4,818k	4,933k	5,035k	5,098k
Absolute poverty, after housing costs: working-age adults	8,445k	8,399k	8,848k	9,001k	9,191k	9,342k	9,400k
Absolute poverty, after housing costs: pensioners	1,521k	1,484k	1,456k	1,493k	1,533k	1,541k	1,551k
Relative poverty, before housing costs: everyone	11,980k	11,485k	11,639k	11,698k	11,596k	11,730k	11,890k
Relative poverty, before housing costs: children	3,967k	3,570k	3,578k	3,587k	3,531k	3,566k	3,616k
Relative poverty, before housing costs: working-age adults	6,227k	6,161k	6,401k	6,485k	6,468k	6,552k	6,616k
Relative poverty, before housing costs: pensioners	1,785k	1,754k	1,660k	1,627k	1,597k	1,611k	1,659k
Relative poverty, after housing costs: everyone	15,057k	14,705k	14,981k	15,071k	15,191k	15,336k	15,683k
Relative poverty, after housing costs: children	5,024k	4,718k	4,751k	4,755k	4,774k	4,816k	4,937k
Relative poverty, after housing costs: working-age adults	8,480k	8,486k	8,784k	8,917k	9,017k	9,112k	9,256k
Relative poverty, after housing costs: pensioners	1,552k	1,501k	1,445k	1,399k	1,399k	1,408k	1,491k

Inequality: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Gini coefficient, equivalised HBAI income before housing costs	0.3087	0.3060	0.3074	0.3080	0.3085	0.3091	0.3102

Mean household net income in each side's own deciles: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Decile 1: mean household_net_income per household	£17,832 †	£18,015 †	£17,980 †	£18,037 †	£18,364 †	£18,545 †	£18,723 †
Decile 2: mean household_net_income per household	£28,135 †	£29,092 †	£28,744 †	£29,163 †	£29,434 †	£29,997 †	£30,442 †
Decile 3: mean household_net_income per household	£34,455 †	£35,681 †	£36,229 †	£36,632 †	£36,967 †	£37,482 †	£38,380 †
Decile 4: mean household_net_income per household	£39,398 †	£41,043 †	£41,970 †	£42,713 †	£43,280 †	£44,024 †	£44,550 †
Decile 5: mean household_net_income per household	£43,698 †	£45,019 †	£45,872 †	£46,588 †	£47,624 †	£48,569 †	£49,772 †
Decile 6: mean household_net_income per household	£48,494 †	£49,775 †	£50,932 †	£51,700 †	£52,150 †	£53,469 †	£54,371 †
Decile 7: mean household_net_income per household	£56,360 †	£57,552 †	£58,380 †	£59,120 †	£60,160 †	£60,882 †	£62,979 †
Decile 8: mean household_net_income per household	£68,817 †	£70,403 †	£71,732 †	£72,842 †	£74,422 †	£75,795 †	£77,575 †
Decile 9: mean household_net_income per household	£79,735 †	£82,088 †	£83,280 †	£84,576 †	£86,144 †	£87,656 †	£90,725 †
Decile 10: mean household_net_income per household	£117,772 †	£120,640 †	£122,567 †	£124,692 †	£126,940 †	£129,209 †	£132,023 †

Standard reform costings (change in gov_balance): head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Raise basic rate by 1pp	£6.22bn	£6.50bn	£6.70bn	£6.90bn	£7.11bn	£7.34bn	£7.62bn
Raise higher rate by 1pp	£3.54bn	£3.82bn	£4.05bn	£4.27bn	£4.49bn	£4.76bn	£4.96bn
Raise personal allowance by ~800GBP/year	£-3.83bn	£-3.96bn	£-4.03bn	£-4.10bn	£-4.19bn	£-4.30bn	£-2.02bn
Raise child benefit by 25GBP/week per additional child	£-2.00bn	£-1.76bn	£-1.64bn	£-1.54bn	£-1.44bn	£-1.34bn	£-1.24bn
Reduce Universal Credit taper rate to 20%	£-20.49bn	£-21.05bn	£-21.40bn	£-21.83bn	£-21.91bn	£-22.28bn	£-22.73bn
Raise Class 1 main employee NICs rate to 10%	£11.07bn	£11.51bn	£11.84bn	£12.14bn	£12.48bn	£12.82bn	£13.29bn
Raise VAT standard rate by 2pp	£25.01bn	£25.68bn	£26.29bn	£26.92bn	£27.58bn	£28.26bn	£28.95bn
Raise additional rate by 3pp	£2.83bn	£3.07bn	£3.27bn	£3.47bn	£3.67bn	£3.91bn	£4.23bn
Raise the Universal Credit standard allowance by 10%	£-3.06bn	£-3.19bn	£-3.27bn	£-3.35bn	£-3.40bn	£-3.46bn	£-3.50bn
Raise the State Pension by 10%	£-7.81bn	£-8.07bn	£-7.99bn	£-8.11bn	£-8.36bn	£-8.66bn	£-9.02bn

Standard reforms: change in each reform's target: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Raise basic rate by 1pp: change in income_tax	£6.36bn	£6.65bn	£6.86bn	£7.07bn	£7.28bn	£7.52bn	£7.80bn
Raise higher rate by 1pp: change in income_tax	£3.55bn	£3.83bn	£4.06bn	£4.28bn	£4.50bn	£4.77bn	£4.97bn
Raise personal allowance by ~800GBP/year: change in income_tax	£-3.96bn	£-4.10bn	£-4.19bn	£-4.26bn	£-4.36bn	£-4.47bn	£-1.77bn
Raise child benefit by 25GBP/week per additional child: change in child_benefit	£2.34bn	£2.15bn	£2.03bn	£1.92bn	£1.82bn	£1.71bn	£1.59bn
Reduce Universal Credit taper rate to 20%: change in universal_credit	£20.48bn	£21.04bn	£21.39bn	£21.82bn	£21.90bn	£22.27bn	£22.73bn
Raise Class 1 main employee NICs rate to 10%: change in national_insurance	£11.33bn	£11.79bn	£12.13bn	£12.44bn	£12.78bn	£13.13bn	£13.62bn
Raise VAT standard rate by 2pp: change in vat	£25.01bn	£25.68bn	£26.29bn	£26.92bn	£27.58bn	£28.26bn	£28.95bn
Raise additional rate by 3pp: change in income_tax	£2.83bn	£3.07bn	£3.27bn	£3.47bn	£3.67bn	£3.91bn	£4.23bn
Raise the Universal Credit standard allowance by 10%: change in universal_credit	£3.06bn	£3.20bn	£3.27bn	£3.35bn	£3.41bn	£3.46bn	£3.51bn
Raise the State Pension by 10%: change in state_pension	£10.72bn	£11.23bn	£11.37bn	£11.62bn	£12.08bn	£12.54bn	£13.07bn

[MaxGhenis]

UK hub independent review (GPT-6.1 Sol) at 41daefdd1: one P2 finding, so it requests changes. All 17 checks pass. The same-year baseline reference covers 2026–29 rebalancing; cap, abolition, penny floor and protected-floor allocation keep their structure; SI 2013/383 reg 10 prescribes no allowance indexation. National UC moves by under £12 a year in 2025–31 on the Aggregate impact report.

• [P2] Missing cash becomes zero in partially supplied populations. uc_advance_repayment_amount.py:19 uses the float default of zero. When one benefit unit supplies cash, Core fills every omitted unit with zero and bypasses the fallback formula. So a 2025 single claimant aged 30 with ADVANCE_ONLY and latent rate 0.1 loses its £480.168 annual fallback whenever another unit supplies an explicit zero. Missingness needs keeping per unit, for example a sentinel default meaning "not supplied", or a separate supplied flag.

As with #2573, and at the coordinator's request so nobody waits, the hub is opening this fix as a separate PR stacked on your branch; it won't push to yours. @juaristi22, cherry-pick it if you'd rather fold it in. Both land together once you mark this ready or say the hub may.

[MaxGhenis]

UC advance missingness fix is pushed as draft #2581, stacked on #2574's fix-uc-advance-cash-2410 branch. Head: 52201202239dfb73ddb5224ceff0753cdc2e4787; parent remains 41daefdd1671b029b8c2c650d30787f586cdd69f. No commits were pushed to the parent branch.

• Change/impact: default -1 preserves omitted units in partially supplied cash arrays. The deduction formula resolves each missing amount through the shared legacy fallback; explicit zero remains zero. Includes fully supplied/unsupplied cases and the £480.168 mixed-zero regression. No aggregate run or data build was performed.
• Tests: full repository uvx ruff format --check . (1937 files), ruff check . and whitespace checks pass. Seven population regressions, a Hypothesis peer-independence property and a mixed-zero YAML case were added. The prepared focused Python/YAML suite (including Keep UC advance repayments fixed under allowance reforms #2574's tests and allowance rebalancing) uses -n 2 in the foreground, frozen Python 3.13.15/Core 3.33.2 and BLAS/OpenMP limits of 2.
• Open items: 0 local tests executed: after 30.9 minutes monitoring the resource gates, free disk remained below the required 55 GB decimal (50.749 GB at stop; load1 26.18, limit 110). The foreground runner was stopped before pytest launched. Retry once host disk space is available; workspace .job/HANDOFF.md contains the exact gated command. Local focused validation and the hub's independent final-head review are still pending. No CI checks were attached to the stacked draft when queried. Keep draft; do not merge or mark ready.

Workspace-local .job/PROGRESS.md, HANDOFF.md, handoffs.jsonl and recovery bundle are available for the hub. Track the narrow P2 in #2578; adopt this stack together with #2574 before the fallback build.

[juaristi22]

Focused validation of the existing #2581 repair is complete at 52201202239dfb73ddb5224ceff0753cdc2e4787, directly on this PR's 41daefdd1671b029b8c2c650d30787f586cdd69f parent: 99 passed, 0 failed, 0 skipped (81 Python tests and 18 YAML cases). Native pytest and the bounded controller both exited 0; pytest took 226.52 seconds.

The single serial run covered all seven new population cases and the Hypothesis peer-independence property, both deduction YAML files, test_uc_deductions.py, test_uc_rebalancing.py and test_uc_standard_allowance_uplift.py. Both existing test_inactive_health_cash_reconciles_with_currentmain_deductions variants passed. This includes the mixed-zero regression for the £480.168 annual fallback.

Execution used an existing Python 3.13.14 / policyengine-core 3.33.2 / NumPy 2.5.4 environment, with imports verified against the exact detached checkout. Core's actual OpenFiscaPlugin(CountryTaxBenefitSystem(), {}) collected the YAML cases in the same pytest invocation. Source and test hashes were unchanged, and the process group was reaped. No environment installation, test rerun or full-population computation was needed.

This supplies the missing focused execution evidence for the parent repair. The hub's independent final-head review remains pending. #2574 remains draft; the repair still needs adoption and validation of the resulting upstream head before readiness and Vahid's review request.

[MaxGhenis]

UK hub: the stack is approved. The independent review (GPT-6.1 Sol) of this PR with the fix #2581 approves at 522012022. The full Code changes run on #2581's branch passed: 4,244 YAML and 8,164 Python tests, with the seven new population cases and the Hypothesis property. With no cash input, the fallback is unchanged.

@juaristi22: as with #2580, merge #2581 into this branch (it fast-forwards), and mark this ready. Or tell the hub it may, and it'll do both and land this through the merge queue.

[juaristi22]

Can you link the full independent review report and result JSON for 522012022? I have verified CI and will reuse the existing test evidence.

[vahid-ahmadi]

Round 1 at 41daefdd1.

Verdict: the approach is right and baseline is unchanged, but this head still has the hub's mixed-population bug; fold in #2581 before marking ready. Comment only, as it is a draft.

Findings

1. must: an explicit cash value on one benefit unit zeroes the fallback for every other unit. uc_advance_repayment_amount.py:19 is a float with the default of 0, so once any unit supplies the variable, Core fills the rest with 0 and the formula at :23 never runs for them. I reproduced it at this head merged with main: two identical single 30-year-olds, latent rate 0.1, ADVANCE_ONLY. With no input both get £480.17 a year; when the second one supplies uc_advance_repayment_amount: 0, the first drops to £0 as well. This is the P2 from the hub review on 22 Oct, and Preserve missing UC advance repayments in mixed populations #2581 (522012022, stacked on this branch, -1 sentinel) fixes it. It is harmless for population runs today, because no dataset supplies the variable yet, but it breaks the documented "set the actual amount when known" route (docs/book/validation/uc-deductions.md, new section) for any mixed situation or future data build. Please fast-forward to Preserve missing UC advance repayments in mixed populations #2581 or cherry-pick it; it already carries the mixed-zero regression.
2. should: the PR body predates the hub review. It says the independent review is "COMPLETE/APPROVE at 41daefdd1 ... with no open findings". The hub review at that sha requested changes (finding 1), and the approval was for 522012022 with Preserve missing UC advance repayments in mixed populations #2581. Please update the body when you adopt the fix, so the record matches.
3. nit: the uplift YAML case (uc_fixed_deductions.yaml:151-190) copies the comment from the case above (:145 and :186, "£21,277.40 before £600"). Since the benefit cap absorbs the uplift and the cash is supplied explicitly, this case shows that the cap offsets the uplift rather than that the advance stays fixed; test_allowance_scenario_preserves_the_legacy_advance_cash_reference is the test that pins the actual fix. Maybe say so in the comment.
4. nit: deduction_type_shares decodes uc_deduction_combination to strings three times (_deduction_amounts.py:12, :24, :36). The old code compared enum values. It is correct, just slower on a full population; decoding once or comparing enums would do.

Law

• SI 2013/383 reg 10 only offsets or deducts payments on account against the award. It sets no instalment and indexes nothing to the allowance, so holding cash demand fixed under an allowance reform is right.
• The deductions ceiling is a share of the standard allowance: SI 2013/380 Sch 6 para 4(1) sets 40%, and DWP runs the 15% Fair Repayment Rate within it (as deductions/cap.yaml records). So the cap should move with the allowance while the advance demand does not, which is what uc_deduction_rate.py now does. The "binding cap" and "penny" YAML cases match.

Current with main: yes. The branch is 765 commits behind 49a7590, but main has not touched any deduction file since the merge base 45c0431a2, and git merge-tree is clean. CI at this head is fully green (17/17), but it ran on 22 Oct, so the rerun after folding in #2581 will cover current main.

What I ran (fresh worktree, this head merged with main 49a7590, Python 3.13, core 3.33.12, serial)

• test_uc_deductions.py, test_uc_rebalancing.py, test_uc_standard_allowance_uplift.py: 73 passed.
• uc_deductions.yaml and uc_fixed_deductions.yaml: 17 passed. The other YAML files that mention UC deductions (HB passport, benefit cap by scheme, benefit cap pension age, CTR pensioner): 50 passed.
• Baseline check against main: 7 combinations x 3 latent rates (0.05, 0.2, 0.4) x 4 claimant types x 2025 to 2030, 504 cells. uc_deductions matches main in every cell (max gap under £0.0001), including the rebalancing years. So the same-year baseline reference does what it says.
• The finding 1 reproducer above.

Not run or read: no full microsimulation or aggregate run (I relied on the CI aggregate report); #2581's diff only as far as its description and the hub's notes; the documentation build; the full YAML and Python suites.

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