juaristi22 · Nov 4, 2026 · Nov 3, 2026 · Nov 3, 2026 · Nov 3, 2026 · Nov 3, 2026
diff --git a/changelog.d/2847.fixed.md b/changelog.d/2847.fixed.md
@@ -0,0 +1 @@
+The Cost of Living Payment amounts now read zero before 2022, so the model no longer pays them in 2015-16 to 2021-22. Following the Social Security (Additional Payments) Acts 2022 and 2023, the model now pays the means-tested payment to each benefit unit on Universal Credit, Pension Credit, income-based JSA, income-related ESA or Income Support, or on Child Tax Credit or Working Tax Credit alone (in 2022-23, with at least £26 of either credit), but not to one on Housing Benefit alone, and pays the £150 disability payment to each person on PIP, DLA, Attendance Allowance or Armed Forces Independence Payment.
diff --git a/docs/book/policy/future-date-announcements.md b/docs/book/policy/future-date-announcements.md
@@ -121,7 +121,10 @@ The same pattern applies in reverse to one-off or time-limited
 payments. The means-tested Cost-of-Living Payment in
 [`gov/treasury/cost_of_living_support/means_tested_households/amount.yaml`](https://github.com/PolicyEngine/policyengine-uk/blob/main/policyengine_uk/parameters/gov/treasury/cost_of_living_support/means_tested_households/amount.yaml)
 is £650 from 2022, £900 from 2023 and goes back to zero from
-2024-01-01.
+2024-01-01. It also reads zero before 2022, from a `0001-01-01: 0` row: the
+model carries each parameter's earliest value back to 2015
+(`backdate_parameters` in `policyengine_uk/utils/parameters.py`), so without
+that row it would pay the one-off amount in every year from 2015.
 
 ## Best practices
 

diff --git a/docs/book/policy/model-baseline.md b/docs/book/policy/model-baseline.md
@@ -66,7 +66,7 @@ The government announced increases to [stamp duty nil rate thresholds](https://g
 
 ### Cost of living support
 
-The government announced cost of living payments: [£650 for means-tested benefit recipients](https://github.com/PolicyEngine/policyengine-uk/blob/master/policyengine_uk/parameters/gov/treasury/cost_of_living_support/means_tested_households/amount.yaml#L3), [£300 for pensioners](https://github.com/PolicyEngine/policyengine-uk/blob/master/policyengine_uk/parameters/gov/treasury/cost_of_living_support/pensioners/amount.yaml#L3), and [£150 for disability benefit recipients](https://github.com/PolicyEngine/policyengine-uk/blob/master/policyengine_uk/parameters/gov/treasury/cost_of_living_support/disabled/amount.yaml#L3), implemented through dedicated [payment calculation variables](https://github.com/PolicyEngine/policyengine-uk/blob/master/policyengine_uk/variables/gov/treasury/cost_of_living_support/cost_of_living_support_payment.py).
+The government announced cost of living payments: [£650 for means-tested benefit recipients](https://github.com/PolicyEngine/policyengine-uk/blob/master/policyengine_uk/parameters/gov/treasury/cost_of_living_support/means_tested_households/amount.yaml#L4), [£300 for pensioners](https://github.com/PolicyEngine/policyengine-uk/blob/master/policyengine_uk/parameters/gov/treasury/cost_of_living_support/pensioners/amount.yaml#L4), and [£150 for disability benefit recipients](https://github.com/PolicyEngine/policyengine-uk/blob/master/policyengine_uk/parameters/gov/treasury/cost_of_living_support/disabled/amount.yaml#L4), implemented through dedicated [payment calculation variables](https://github.com/PolicyEngine/policyengine-uk/blob/master/policyengine_uk/variables/gov/treasury/cost_of_living_support/cost_of_living_support_payment.py).
 
 ### Energy Price Guarantee
 

diff --git a/docs/book/programs/gov/treasury/cost-of-living-payments.md b/docs/book/programs/gov/treasury/cost-of-living-payments.md
@@ -111,32 +111,60 @@ so a household whose survey record has no band qualifies.
 
 ## Cost-of-Living Payments (2022-23 and 2023-24)
 
-Two successive packages, both modelled through the variable
-`cost_of_living_support_payment` at `gov/treasury/cost_of_living_support/`.
-The variable returns the **sum** of three independent strands depending
-on which qualifying benefits the household receives:
+The model pays two successive packages through the household variable
+`cost_of_living_support_payment`, with parameters at
+`gov/treasury/cost_of_living_support/`. The variable returns the **sum** of
+three strands: the means-tested payment to each benefit unit, the disability
+payment to each person and the pensioner payment to the household.
 
 | Strand | 2022-23 | 2023-24 | Qualifying benefits |
 |--------|---------|---------|---------------------|
-| Means-tested CoL Payment | £650 (two instalments) | £900 (three instalments) | Universal Credit, Pension Credit, Housing Benefit, income-based JSA / ESA, Income Support |
+| Means-tested CoL Payment | £650 (two instalments) | £900 (three instalments) | Universal Credit, Pension Credit, income-based JSA, income-related ESA or Income Support; or Child Tax Credit or Working Tax Credit and none of those (an award of at least £26 for the year in 2022-23) |
 | Pensioner CoL Payment    | £300 | £300 | Winter Fuel Payment recipients |
-| Disability CoL Payment   | £150 | £150 | DLA, PIP, Attendance Allowance, AFCS, IIDB, SDA, child / war disability pension |
+| Disability CoL Payment   | £150 | £150 | DLA, PIP, Attendance Allowance or Armed Forces Independence Payment |
 
-From 2024-01-01 the parameter values are explicitly reset to zero so the
-one-off doesn't extrapolate forward.
+From 2024-01-01 the amounts read zero, so the one-off payments don't
+extrapolate forward. The amounts also read zero before 2022, so although the
+model carries each parameter's earliest value back to 2015, it pays nothing
+in 2015-16 to 2021-22.
 
 ### How PolicyEngine computes the payment
 
-For each strand `s ∈ {means_tested_households, pensioners, disabled}`:
-
-```
-on_s = (sum of household's reported amounts in s.qualifying_benefits) > 0
-strand_s = s.amount(period) * on_s
-```
-
-Total `cost_of_living_support_payment = means_test_bonus + pensioner_bonus + disabled_bonus`,
-i.e. the strands stack — a pensioner on Pension Credit who also receives PIP
-will collect all three payments. This matches the actual policy.
+Under the Social Security (Additional Payments) Acts 2022 and 2023, the
+Secretary of State and HMRC pay the means-tested payment to each "person",
+meaning an individual or a couple (section 1(6) of the 2022 Act, section 1(9)
+of the 2023 Act), and the Secretary of State pays the disability payment to
+each individual (section 5(1)). Three variables model these payments:
+
+- `cost_of_living_means_tested_payment` (benefit unit) pays
+  `means_tested_households.amount` to a benefit unit with any of
+  `means_tested_households.qualifying_benefits` (section 1(1) and (3)), or
+  with none of them and a yearly award of either credit in
+  `means_tested_households.qualifying_tax_credits` that reaches
+  `means_tested_households.minimum_tax_credit_award` (section 1(2)).
+  Parliament set that minimum at £26 for 2022-23 (section 2(2) of the 2022
+  Act) and set none for 2023-24 (section 3(1) of the 2023 Act). A unit with
+  both a benefit and a tax credit gets one payment.
+- `cost_of_living_disability_payment` (person) pays `disabled.amount` to a
+  person with any of `disabled.qualifying_benefits`.
+- `cost_of_living_support_payment` (household) adds both over the
+  household's benefit units and members, and adds `pensioners.amount` once
+  if the household has any of `pensioners.qualifying_benefits` (the Winter
+  Fuel Payment).
+
+So a household with a pensioner couple on Pension Credit and an adult son on
+Universal Credit gets two means-tested payments, and a couple both on PIP
+gets two disability payments. The strands stack: a pensioner on Pension
+Credit and Attendance Allowance with a Winter Fuel Payment collects all
+three.
+
+The model holds yearly amounts, so it tests receipt of each benefit and tax
+credit over the year rather than in the month ending with each qualifying
+day, and compares each tax credit's yearly award with the £26 minimum. It
+has no variables for the other disability benefits that Parliament listed
+in section 5(2) (constant attendance allowance, Adult Disability Payment, Child Disability
+Payment and the mobility supplement), so it pays no disability
+payment to someone who gets only those.
 
 ## References
 
@@ -145,3 +173,5 @@ will collect all three payments. This matches the actual policy.
 - HMT, [Energy Bills Support Scheme](https://www.gov.uk/government/publications/the-energy-bills-support-scheme-explainer) and [Council Tax Energy Rebate](https://www.gov.uk/government/publications/the-council-tax-rebate-2022-23-billing-authority-guidance).
 - DWP, [HBAI quality and methodology information report, FYE 2023](https://www.gov.uk/government/statistics/households-below-average-income-for-financial-years-ending-1995-to-2023/households-below-average-income-series-quality-and-methodology-information-report-fye-2023) (treatment of the cost-of-living support schemes in HBAI income).
 - House of Commons Library briefing [CBP-9501 — Cost of Living Payments and the energy crisis](https://commonslibrary.parliament.uk/research-briefings/cbp-9501/).
+- [Social Security (Additional Payments) Act 2022](https://www.legislation.gov.uk/ukpga/2022/38), sections 1 to 5 (the 2022-23 means-tested and disability payments).
+- [Social Security (Additional Payments) Act 2023](https://www.legislation.gov.uk/ukpga/2023/7), sections 1 to 5 (the 2023-24 means-tested and disability payments).
diff --git a/policyengine_uk/parameters/gov/treasury/cost_of_living_support/disabled/amount.yaml b/policyengine_uk/parameters/gov/treasury/cost_of_living_support/disabled/amount.yaml
@@ -1,5 +1,6 @@
-description: One-off Disability Cost-of-Living Payment to households containing someone on a qualifying disability benefit. £150 in both 2022-23 and 2023-24, withdrawn from 2024-25.
+description: Disability Cost of Living Payment to each person on a qualifying disability benefit. Parliament set £150 in section 5(1) of both the Social Security (Additional Payments) Act 2022 and the Social Security (Additional Payments) Act 2023. The model pays it in 2022-23 and 2023-24, and the amount reads zero before 2022 and from 2024.
 values:
+  0001-01-01: 0
   2022-01-01: 150
   2023-01-01: 150
   2024-01-01: 0
@@ -8,6 +9,10 @@ metadata:
   period: year
   label: Disability Cost-of-Living Payment
   reference:
+    - title: Social Security (Additional Payments) Act 2022, section 5(1)
+      href: https://www.legislation.gov.uk/ukpga/2022/38/section/5
+    - title: Social Security (Additional Payments) Act 2023, section 5(1)
+      href: https://www.legislation.gov.uk/ukpga/2023/7/section/5
     - title: 2022-23 Cost-of-Living Support package announcement (HMT/DWP, May 2022)
       href: https://www.gov.uk/government/news/millions-of-most-vulnerable-households-will-receive-1200-of-help-with-cost-of-living
     - title: Disability Cost-of-Living Payment 2023-24 (DWP guidance)

diff --git a/...ngine_uk/parameters/gov/treasury/cost_of_living_support/disabled/qualifying_benefits.yaml b/...ngine_uk/parameters/gov/treasury/cost_of_living_support/disabled/qualifying_benefits.yaml
@@ -1,10 +1,13 @@
-description: Benefits which confer eligibility to the household payment to disability
-  benefits.
+description: Disability benefits that qualify a person for the Disability Cost of Living Payment. The list follows section 5(2) of the Social Security (Additional Payments) Act 2022 and of the Social Security (Additional Payments) Act 2023. The model has no variables for the other benefits Parliament listed there (constant attendance allowance, Adult Disability Payment, Child Disability Payment and the mobility supplement), so it pays nobody who gets only those.
 metadata:
   economy: false
   label: Qualifying benefits for support for disabled households
   propagate_metadata_to_children: true
   reference:
+  - href: https://www.legislation.gov.uk/ukpga/2022/38/section/5
+    title: Social Security (Additional Payments) Act 2022, section 5(2)
+  - href: https://www.legislation.gov.uk/ukpga/2023/7/section/5
+    title: Social Security (Additional Payments) Act 2023, section 5(2)
   - href: https://www.gov.uk/government/news/millions-of-most-vulnerable-households-will-receive-1200-of-help-with-cost-of-living
     title: Cost-of-living support announcement | GOV.UK
   unit: variable

diff --git a/...ine_uk/parameters/gov/treasury/cost_of_living_support/means_tested_households/amount.yaml b/...ine_uk/parameters/gov/treasury/cost_of_living_support/means_tested_households/amount.yaml
@@ -1,5 +1,6 @@
-description: One-off Cost-of-Living Payment to households on qualifying means-tested benefits. £650 across 2022-23 (Spring £326 + Autumn £324) and £900 across 2023-24 (Spring £301 + Autumn £300 + Spring 2024 £299).
+description: Yearly total of the means-tested Cost of Living Payments to each benefit unit on a qualifying benefit or tax credit. Parliament set £326 and £324 in the Social Security (Additional Payments) Act 2022, £650 in all, and £301, £300 and £299 in the Social Security (Additional Payments) Act 2023, £900 in all. The model pays the 2022 Act's amounts in 2022-23 and the 2023 Act's in 2023-24, and the amount reads zero before 2022 and from 2024.
 values:
+  0001-01-01: 0
   2022-01-01: 650
   2023-01-01: 900
   2024-01-01: 0
@@ -8,6 +9,10 @@ metadata:
   period: year
   label: Cost-of-Living Payment (means-tested)
   reference:
+    - title: Social Security (Additional Payments) Act 2022, section 1(1) and (2)
+      href: https://www.legislation.gov.uk/ukpga/2022/38/section/1
+    - title: Social Security (Additional Payments) Act 2023, section 1(1) and (2)
+      href: https://www.legislation.gov.uk/ukpga/2023/7/section/1
     - title: 2022-23 Cost-of-Living Support package announcement (HMT/DWP, May 2022)
       href: https://www.gov.uk/government/news/millions-of-most-vulnerable-households-will-receive-1200-of-help-with-cost-of-living
     - title: 2023-24 Cost-of-Living Payments (Autumn Statement 2022, DWP guidance)

diff --git a/...gov/treasury/cost_of_living_support/means_tested_households/minimum_tax_credit_award.yaml b/...gov/treasury/cost_of_living_support/means_tested_households/minimum_tax_credit_award.yaml
@@ -0,0 +1,15 @@
+description: Smallest yearly award of a qualifying tax credit that qualifies a benefit unit for the means-tested Cost of Living Payment through the tax credit route. Under section 2(2) of the Social Security (Additional Payments) Act 2022, a credit counts in 2022-23 only where the payment or award of that credit comes to at least £26, or HMRC expects at least £26 of it for the tax year 2022-23, and under section 4 HMRC makes final payments where the payments or award of a credit for 2022-23 come to at least £26. Parliament set no such minimum in section 3(1) of the Social Security (Additional Payments) Act 2023. The model holds yearly amounts, so the formula compares each credit's yearly award with this amount.
+values:
+  2022-01-01: 26
+  2023-01-01: 0
+metadata:
+  unit: currency-GBP
+  period: year
+  label: Minimum tax credit award for the means-tested Cost-of-Living Payment
+  reference:
+    - title: Social Security (Additional Payments) Act 2022, section 2(2)
+      href: https://www.legislation.gov.uk/ukpga/2022/38/section/2
+    - title: Social Security (Additional Payments) Act 2022, section 4
+      href: https://www.legislation.gov.uk/ukpga/2022/38/section/4
+    - title: Social Security (Additional Payments) Act 2023, section 3(1)
+      href: https://www.legislation.gov.uk/ukpga/2023/7/section/3
diff --git a/...ters/gov/treasury/cost_of_living_support/means_tested_households/qualifying_benefits.yaml b/...ters/gov/treasury/cost_of_living_support/means_tested_households/qualifying_benefits.yaml
@@ -1,18 +1,20 @@
-description: Benefits which confer eligibility to the household payment to means-tested
-  benefits.
+description: Means-tested benefits that qualify a benefit unit for the means-tested Cost of Living Payment. In section 1(3) of the Social Security (Additional Payments) Act 2022 and of the Social Security (Additional Payments) Act 2023, Parliament listed Universal Credit, Pension Credit, income-based Jobseeker's Allowance, income-related Employment and Support Allowance and Income Support, and left out Housing Benefit.
 metadata:
   economy: false
   label: Qualifying benefits for support for means-tested households
   propagate_metadata_to_children: true
   reference:
+  - href: https://www.legislation.gov.uk/ukpga/2022/38/section/1
+    title: Social Security (Additional Payments) Act 2022, section 1(3)
+  - href: https://www.legislation.gov.uk/ukpga/2023/7/section/1
+    title: Social Security (Additional Payments) Act 2023, section 1(3)
   - href: https://www.gov.uk/government/news/millions-of-most-vulnerable-households-will-receive-1200-of-help-with-cost-of-living
     title: Cost-of-living support announcement | GOV.UK
   unit: variable
 values:
   2022-01-01:
   - universal_credit
   - pension_credit
-  - housing_benefit
   - jsa_income
-  - income_support
   - esa_income
+  - income_support
diff --git a/...s/gov/treasury/cost_of_living_support/means_tested_households/qualifying_tax_credits.yaml b/...s/gov/treasury/cost_of_living_support/means_tested_households/qualifying_tax_credits.yaml
@@ -0,0 +1,15 @@
+description: Tax credits that qualify a benefit unit for the means-tested Cost of Living Payment when it gets none of the qualifying benefits. Under section 1(2) of the Social Security (Additional Payments) Act 2022 and of the Social Security (Additional Payments) Act 2023, HMRC pays a person with a qualifying entitlement to Child Tax Credit or Working Tax Credit but not to a qualifying benefit.
+metadata:
+  economy: false
+  label: Qualifying tax credits for support for means-tested households
+  propagate_metadata_to_children: true
+  reference:
+  - href: https://www.legislation.gov.uk/ukpga/2022/38/section/1
+    title: Social Security (Additional Payments) Act 2022, section 1(2)
+  - href: https://www.legislation.gov.uk/ukpga/2023/7/section/1
+    title: Social Security (Additional Payments) Act 2023, section 1(2)
+  unit: variable
+values:
+  2022-01-01:
+  - child_tax_credit
+  - working_tax_credit
diff --git a/policyengine_uk/parameters/gov/treasury/cost_of_living_support/pensioners/amount.yaml b/policyengine_uk/parameters/gov/treasury/cost_of_living_support/pensioners/amount.yaml
@@ -1,5 +1,6 @@
-description: One-off Pensioner Cost-of-Living Payment paid as a top-up to the Winter Fuel Payment to households containing someone of State Pension age. £300 in both winter 2022-23 and winter 2023-24, withdrawn from winter 2024-25.
+description: One-off Pensioner Cost-of-Living Payment, a £300 top-up to the Winter Fuel Payment, which the formula pays once to each household with a Winter Fuel Payment in 2022-23 and 2023-24. The amount reads zero before 2022 and from 2024.
 values:
+  0001-01-01: 0
   2022-01-01: 300
   2023-01-01: 300
   2024-01-01: 0
@@ -11,4 +12,4 @@ metadata:
     - title: 2022-23 Cost-of-Living Support package announcement (HMT/DWP, May 2022)
       href: https://www.gov.uk/government/news/millions-of-most-vulnerable-households-will-receive-1200-of-help-with-cost-of-living
     - title: Pensioner Cost-of-Living Payment 2023-24 (DWP guidance)
-      href: https://www.gov.uk/guidance/cost-of-living-payment-pensioner
+      href: https://www.gov.uk/guidance/cost-of-living-payment#pensioner-cost-of-living-payment
diff --git a/policyengine_uk/programs.yaml b/policyengine_uk/programs.yaml
@@ -596,10 +596,22 @@ programs:
     agency: Treasury
     status: complete
     coverage: UK
+    variable: cost_of_living_support_payment
     parameter_prefix: gov.treasury.cost_of_living_support
     verified_start_year: 2022
     verified_end_year: 2023
-    notes: Temporary program, ended 2023
+    notes: >-
+      Temporary programme, paid in 2022-23 and 2023-24. The model pays the
+      means-tested payment to each benefit unit on Universal Credit, Pension
+      Credit, income-based JSA, income-related ESA or Income Support, or on
+      Child Tax Credit or Working Tax Credit and none of those (in 2022-23,
+      at least £26 of either credit for the year), the disability payment to
+      each person on PIP, DLA, Attendance Allowance or Armed Forces
+      Independence Payment, and the pensioner payment to each household with
+      a Winter Fuel Payment. It tests receipt over the year, not in the month
+      ending with each qualifying day, and has no variables for constant
+      attendance allowance, Adult Disability Payment, Child Disability
+      Payment or the mobility supplement.
 
   - id: energy_bills_rebate
     name: Energy Bills Rebate
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		The Cost of Living Payment amounts now read zero before 2022, so the model no longer pays them in 2015-16 to 2021-22. Following the Social Security (Additional Payments) Acts 2022 and 2023, the model now pays the means-tested payment to each benefit unit on Universal Credit, Pension Credit, income-based JSA, income-related ESA or Income Support, or on Child Tax Credit or Working Tax Credit alone (in 2022-23, with at least £26 of either credit), but not to one on Housing Benefit alone, and pays the £150 disability payment to each person on PIP, DLA, Attendance Allowance or Armed Forces Independence Payment.