anth-volk · Oct 2, 2026 · Oct 5, 2026 · Oct 5, 2026 · Oct 6, 2026 · Oct 6, 2026
diff --git a/changelog.d/2072.fixed.md b/changelog.d/2072.fixed.md
@@ -0,0 +1 @@
+- Corrects the Pension Credit standard minimum guarantee projection to follow the statutory May-July earnings input with a non-negative floor.
diff --git a/changelog.d/2083.fixed.md b/changelog.d/2083.fixed.md
@@ -0,0 +1 @@
+- Corrected the 2025-26 Pension Credit rates and derived future Savings Credit thresholds from the earnings-projected guarantee and CPI-projected maximum without replacing explicit or reformed threshold values.
diff --git a/changelog.d/2154.fixed.md b/changelog.d/2154.fixed.md
@@ -0,0 +1 @@
+- Correct the 2025-26 rates and forecast basis for protected single, lone-parent, and couple pension-age Housing Benefit personal allowances.
diff --git a/docs/book/programs/gov/dwp/state-pension.md b/docs/book/programs/gov/dwp/state-pension.md
@@ -210,6 +210,15 @@ statutory-basis forecast minus the calendar-year growth stored in
   OBR does not forecast the ONS AWE series; its measure is wages and
   salaries per employee, and Q2 is the quarter nearest May to July.
 
+The State Pension triple lock consumes both statutory inputs. The shared
+`indices.statutory_earnings_floor` series, which floors May-July earnings at
+zero, also projects the Pension Credit standard minimum guarantee. The model
+derives the Savings Credit threshold so that this earnings-projected guarantee
+and a non-negative September CPI projection of maximum Savings Credit preserve
+the statutory 60% relationship. Protected pension-age Housing Benefit uses
+the same earnings and CPI components. These are forecast conventions after
+the last enacted rates, not announced future benefit amounts.
+
 After the EFO horizon the gap is zero, so the inputs follow calendar-year
 growth. Smooth forecasts pay the higher of earnings, CPI and 2.5% each year,
 so the baseline has none of the extra cost the triple lock builds up when

diff --git a/policyengine_uk/parameters/gov/dwp/housing_benefit/allowances/couple/aged.yaml b/policyengine_uk/parameters/gov/dwp/housing_benefit/allowances/couple/aged.yaml
@@ -1,4 +1,7 @@
-description: Personal allowance for Housing Benefit for a couple where one or both members attained State Pension age before 1 April 2021 (and, before that date, every couple with a member over State Pension age).
+description: >-
+  Personal allowance for Housing Benefit for a couple where one or both members attained State Pension age before 1 April 2021 (and, before that date, every couple with a member over State Pension age).
+  Amounts after the last enacted rate use a component-weighted forecast and
+  are not enacted future rates.
 values:
   # 2020-21 to 2026-27: DWP Benefit and pension rates (gov.uk), each
   # year's rate as listed in that year's publication.
@@ -8,19 +11,32 @@ values:
   2022-04-06: 294.9
   2023-04-01: 324.7
   2024-04-01: 352
-  2025-04-01: 366
+  2025-04-01:
+    value: 366
+    metadata:
+      reference:
+        - title: The Social Security Benefits Up-rating Order 2025, Schedule 6 paragraph 1(2)(b)
+          href: https://www.legislation.gov.uk/uksi/2025/295/schedule/6/made
+        - title: The Social Security Benefits Up-rating Order (Northern Ireland) 2025, Schedule 6 paragraph 1(2)(b)
+          href: https://www.legislation.gov.uk/nisr/2025/64/schedule/6/made
+        - title: Benefit and pension rates 2025 to 2026, Housing Benefit personal allowances
+          href: https://www.gov.uk/government/publications/benefit-and-pension-rates-2025-to-2026/benefit-and-pension-rates-2025-to-2026
   2026-04-01: 383.35
 
 metadata:
   period: week
   unit: currency-GBP
   label: Housing Benefit couple pension-age personal allowance
-  uprating: gov.benefit_uprating_cpi
+  uprating: gov.dwp.housing_benefit.allowances.protected_pension_age_uprating.couple
   reference:
     - title: The Housing Benefit (Persons who have attained the qualifying age for state pension credit) Regulations 2006 (SI 2006/214), Schedule 3, paragraph 1(2)(b)
       href: https://www.legislation.gov.uk/uksi/2006/214/schedule/3
     - title: The Housing Benefit (Persons who have attained the qualifying age for state pension credit) Regulations (Northern Ireland) 2006 (SR 2006/406), Schedule 4, paragraph 1 (the same amounts)
       href: https://www.legislation.gov.uk/nisr/2006/406/schedule/4
+    - title: The Housing Benefit (Persons who have attained the qualifying age for state pension credit) Regulations 2006 Schedule 3 paragraph 1
+      href: https://www.legislation.gov.uk/uksi/2006/214/schedule/3/paragraph/1
+    - title: The Social Security Benefits Up-rating Order 2026 article 24(6) and Schedule 6
+      href: https://www.legislation.gov.uk/uksi/2026/148/schedule/6/made
     - title: Benefit and pension rates 2024 to 2025 - Policy paper
       href: https://www.gov.uk/government/publications/benefit-and-pension-rates-2024-to-2025/benefit-and-pension-rates-2024-to-2025
     - title: Benefit and pension rates 2020 to 2021 (DWP, gov.uk)
@@ -33,3 +49,5 @@ metadata:
       href: https://www.legislation.gov.uk/uksi/2025/295/contents/made
     - title: The Social Security Benefits Up-rating Order 2026 (SI 2026/148)
       href: https://www.legislation.gov.uk/uksi/2026/148/contents/made
+    - title: A14/2025 Housing Benefit uprating for the financial year ending March 2027, paragraphs 5, 6 and 20
+      href: https://www.gov.uk/government/publications/housing-benefit-adjudication-circulars-2025/a142025-housing-benefit-uprating-for-the-financial-year-ending-march-2027
diff --git a/...uk/parameters/gov/dwp/housing_benefit/allowances/create_protected_pension_age_uprating.py b/...uk/parameters/gov/dwp/housing_benefit/allowances/create_protected_pension_age_uprating.py
@@ -0,0 +1,185 @@
+"""Project protected pension-age Housing Benefit allowances by component.
+
+The protected allowances consist of the corresponding Pension Credit
+standard minimum guarantee plus a retained Savings Credit uplift. The
+guarantee component follows the shared statutory earnings index; the retained
+uplift follows non-negative September CPI. Projecting either whole allowance
+with one series would therefore misstate its relationship to Pension Credit.
+"""
+
+from policyengine_core.parameters import Parameter, ParameterNode
+
+from policyengine_uk.parameters.gov.economic_assumptions.create_statutory_uprating_inputs import (
+    CPI_OBSERVATION_MONTH_DAY,
+    last_input_year,
+)
+
+
+BASE_YEAR = 2026
+BASE_INSTANT = f"{BASE_YEAR}-04-01"
+
+
+def project_retained_uplift(amount: float, cpi_growth: float) -> float:
+    """Project the retained Savings Credit uplift without a cash reduction."""
+    return amount * (1 + max(cpi_growth, 0))
+
+
+def protected_allowance_index_values(
+    base_allowance: float,
+    guarantee_component: float,
+    earnings_index: Parameter,
+    cpi_september: Parameter,
+    final_observation_year: int,
+) -> dict[str, float]:
+    """Build a component-weighted index from the last enacted allowance."""
+    retained_uplift = base_allowance - guarantee_component
+    if retained_uplift < 0:
+        raise ValueError(
+            "The protected Housing Benefit allowance cannot be lower than "
+            "the corresponding Pension Credit guarantee."
+        )
+
+    base_earnings_index = float(earnings_index(BASE_INSTANT))
+    values = {BASE_INSTANT: 1.0}
+    for year in range(BASE_YEAR + 1, final_observation_year + 2):
+        observation_year = year - 1
+        guarantee = guarantee_component * (
+            float(earnings_index(f"{year}-04-01")) / base_earnings_index
+        )
+        retained_uplift = project_retained_uplift(
+            retained_uplift,
+            float(cpi_september(f"{observation_year}-{CPI_OBSERVATION_MONTH_DAY}")),
+        )
+        values[f"{year}-04-01"] = (guarantee + retained_uplift) / base_allowance
+    return values
+
+
+def _projection_parameter(
+    relationship: str,
+    base_allowance: float,
+    guarantee_component: float,
+    earnings_index: Parameter,
+    cpi_september: Parameter,
+    final_observation_year: int,
+) -> Parameter:
+    retained_uplift = base_allowance - guarantee_component
+    relationship_label = (
+        "single and lone-parent" if relationship == "single" else "couple"
+    )
+    return Parameter(
+        (
+            "gov.dwp.housing_benefit.allowances."
+            f"protected_pension_age_uprating.{relationship}"
+        ),
+        data={
+            "description": (
+                f"Forecast index for the protected {relationship_label} "
+                "pension-age Housing Benefit allowance. The enacted 2026-27 "
+                f"base comprises a £{guarantee_component:g} Pension Credit "
+                f"guarantee and a £{retained_uplift:g} retained Savings "
+                "Credit uplift. The components follow the shared statutory "
+                "earnings index and non-negative September CPI, respectively. "
+                "Projected values are not enacted rates."
+            ),
+            "values": protected_allowance_index_values(
+                base_allowance,
+                guarantee_component,
+                earnings_index,
+                cpi_september,
+                final_observation_year,
+            ),
+            "metadata": {
+                "unit": "/1",
+                "label": (
+                    f"Protected {relationship_label} pension-age Housing "
+                    "Benefit allowance forecast index"
+                ),
+                "reference": [
+                    {
+                        "title": (
+                            "Social Security Administration Act 1992 section 150"
+                        ),
+                        "href": (
+                            "https://www.legislation.gov.uk/ukpga/1992/5/section/150"
+                        ),
+                    },
+                    {
+                        "title": (
+                            "Social Security Administration Act 1992 section 150A"
+                        ),
+                        "href": (
+                            "https://www.legislation.gov.uk/ukpga/1992/5/section/150A"
+                        ),
+                    },
+                    {
+                        "title": (
+                            "A14/2025 Housing Benefit uprating for the "
+                            "financial year ending March 2027, paragraphs "
+                            "5, 6 and 20"
+                        ),
+                        "href": (
+                            "https://www.gov.uk/government/publications/"
+                            "housing-benefit-adjudication-circulars-2025/"
+                            "a142025-housing-benefit-uprating-for-the-"
+                            "financial-year-ending-march-2027"
+                        ),
+                    },
+                    {
+                        "title": (
+                            "ONS KAC3 average weekly earnings, whole economy, total pay"
+                        ),
+                        "href": (
+                            "https://www.ons.gov.uk/"
+                            "employmentandlabourmarket/peopleinwork/"
+                            "earningsandworkinghours/timeseries/kac3/lms"
+                        ),
+                    },
+                    {
+                        "title": "ONS D7G7 Consumer Prices Index annual rate",
+                        "href": (
+                            "https://www.ons.gov.uk/economy/"
+                            "inflationandpriceindices/timeseries/d7g7/mm23"
+                        ),
+                    },
+                ],
+            },
+        },
+    )
+
+
+def add_protected_pension_age_uprating(
+    parameters: ParameterNode,
+) -> ParameterNode:
+    """Add relationship-specific protected-allowance forecast indices."""
+    allowances = parameters.gov.dwp.housing_benefit.allowances
+    guarantees = parameters.gov.dwp.pension_credit.guarantee_credit.minimum_guarantee
+    earnings_index = (
+        parameters.gov.economic_assumptions.indices.statutory_earnings_floor
+    )
+    cpi_september = (
+        parameters.gov.economic_assumptions.statutory_uprating_inputs.cpi_september
+    )
+    projection = ParameterNode(
+        name=("gov.dwp.housing_benefit.allowances.protected_pension_age_uprating"),
+        data={},
+    )
+    allowances.add_child("protected_pension_age_uprating", projection)
+
+    relationship_parameters = {
+        "single": (allowances.single.aged, guarantees.SINGLE),
+        "couple": (allowances.couple.aged, guarantees.COUPLE),
+    }
+    final_observation_year = last_input_year(parameters)
+    for relationship, (allowance, guarantee) in relationship_parameters.items():
+        projection.add_child(
+            relationship,
+            _projection_parameter(
+                relationship,
+                float(allowance(BASE_INSTANT)),
+                float(guarantee(BASE_INSTANT)),
+                earnings_index,
+                cpi_september,
+                final_observation_year,
+            ),
+        )
+    return parameters
diff --git a/policyengine_uk/parameters/gov/dwp/housing_benefit/allowances/lone_parent/aged.yaml b/policyengine_uk/parameters/gov/dwp/housing_benefit/allowances/lone_parent/aged.yaml
@@ -1,4 +1,7 @@
-description: Personal allowance for Housing Benefit for a lone parent who attained State Pension age before 1 April 2021 (and, before that date, every pension-age lone parent).
+description: >-
+  Personal allowance for Housing Benefit for a lone parent who attained State Pension age before 1 April 2021 (and, before that date, every pension-age lone parent).
+  Amounts after the last enacted rate use a component-weighted forecast and
+  are not enacted future rates.
 
 values:
   # 2020-21 to 2026-27: DWP Benefit and pension rates (gov.uk), each
@@ -9,19 +12,32 @@ values:
   2022-04-06: 197.1
   2023-04-01: 217
   2024-04-01: 235.2
-  2025-04-01: 244.4
+  2025-04-01:
+    value: 244.4
+    metadata:
+      reference:
+        - title: The Social Security Benefits Up-rating Order 2025, Schedule 6 paragraph 1(1)(b)
+          href: https://www.legislation.gov.uk/uksi/2025/295/schedule/6/made
+        - title: The Social Security Benefits Up-rating Order (Northern Ireland) 2025, Schedule 6 paragraph 1(1)(b)
+          href: https://www.legislation.gov.uk/nisr/2025/64/schedule/6/made
+        - title: Benefit and pension rates 2025 to 2026, Housing Benefit personal allowances
+          href: https://www.gov.uk/government/publications/benefit-and-pension-rates-2025-to-2026/benefit-and-pension-rates-2025-to-2026
   2026-04-01: 256
 
 metadata:
   period: week
   unit: currency-GBP
   label: Housing Benefit lone parent pension-age personal allowance
-  uprating: gov.benefit_uprating_cpi
+  uprating: gov.dwp.housing_benefit.allowances.protected_pension_age_uprating.single
   reference:
     - title: The Housing Benefit (Persons who have attained the qualifying age for state pension credit) Regulations 2006 (SI 2006/214), Schedule 3, paragraph 1(1)(b)
       href: https://www.legislation.gov.uk/uksi/2006/214/schedule/3
     - title: The Housing Benefit (Persons who have attained the qualifying age for state pension credit) Regulations (Northern Ireland) 2006 (SR 2006/406), Schedule 4, paragraph 1 (the same amounts)
       href: https://www.legislation.gov.uk/nisr/2006/406/schedule/4
+    - title: The Housing Benefit (Persons who have attained the qualifying age for state pension credit) Regulations 2006 Schedule 3 paragraph 1
+      href: https://www.legislation.gov.uk/uksi/2006/214/schedule/3/paragraph/1
+    - title: The Social Security Benefits Up-rating Order 2026 article 24(6) and Schedule 6
+      href: https://www.legislation.gov.uk/uksi/2026/148/schedule/6/made
     - title: Benefit and pension rates 2024 to 2025 - Policy paper
       href: https://www.gov.uk/government/publications/benefit-and-pension-rates-2024-to-2025/benefit-and-pension-rates-2024-to-2025
     - title: Benefit and pension rates 2020 to 2021 (DWP, gov.uk)
@@ -34,3 +50,5 @@ metadata:
       href: https://www.legislation.gov.uk/uksi/2025/295/contents/made
     - title: The Social Security Benefits Up-rating Order 2026 (SI 2026/148)
       href: https://www.legislation.gov.uk/uksi/2026/148/contents/made
+    - title: A14/2025 Housing Benefit uprating for the financial year ending March 2027, paragraphs 5 and 20
+      href: https://www.gov.uk/government/publications/housing-benefit-adjudication-circulars-2025/a142025-housing-benefit-uprating-for-the-financial-year-ending-march-2027
diff --git a/policyengine_uk/parameters/gov/dwp/housing_benefit/allowances/single/aged.yaml b/policyengine_uk/parameters/gov/dwp/housing_benefit/allowances/single/aged.yaml
@@ -1,4 +1,7 @@
-description: Personal allowance for Housing Benefit for a single claimant who attained State Pension age before 1 April 2021 (and, before that date, every single pension-age claimant).
+description: >-
+  Personal allowance for Housing Benefit for a single claimant who attained State Pension age before 1 April 2021 (and, before that date, every single pension-age claimant).
+  Amounts after the last enacted rate use a component-weighted forecast and
+  are not enacted future rates.
 values:
   # 2020-21 to 2026-27: DWP Benefit and pension rates (gov.uk), each
   # year's rate as listed in that year's publication.
@@ -8,19 +11,32 @@ values:
   2022-04-06: 197.1
   2023-04-01: 217
   2024-04-01: 235.2
-  2025-04-01: 244.4
+  2025-04-01:
+    value: 244.4
+    metadata:
+      reference:
+        - title: The Social Security Benefits Up-rating Order 2025, Schedule 6 paragraph 1(1)(b)
+          href: https://www.legislation.gov.uk/uksi/2025/295/schedule/6/made
+        - title: The Social Security Benefits Up-rating Order (Northern Ireland) 2025, Schedule 6 paragraph 1(1)(b)
+          href: https://www.legislation.gov.uk/nisr/2025/64/schedule/6/made
+        - title: Benefit and pension rates 2025 to 2026, Housing Benefit personal allowances
+          href: https://www.gov.uk/government/publications/benefit-and-pension-rates-2025-to-2026/benefit-and-pension-rates-2025-to-2026
   2026-04-01: 256
 
 metadata:
   period: week
   unit: currency-GBP
   label: Housing Benefit single pension-age personal allowance
-  uprating: gov.benefit_uprating_cpi
+  uprating: gov.dwp.housing_benefit.allowances.protected_pension_age_uprating.single
   reference:
     - title: The Housing Benefit (Persons who have attained the qualifying age for state pension credit) Regulations 2006 (SI 2006/214), Schedule 3, paragraph 1(1)(b)
       href: https://www.legislation.gov.uk/uksi/2006/214/schedule/3
     - title: The Housing Benefit (Persons who have attained the qualifying age for state pension credit) Regulations (Northern Ireland) 2006 (SR 2006/406), Schedule 4, paragraph 1 (the same amounts)
       href: https://www.legislation.gov.uk/nisr/2006/406/schedule/4
+    - title: The Housing Benefit (Persons who have attained the qualifying age for state pension credit) Regulations 2006 Schedule 3 paragraph 1
+      href: https://www.legislation.gov.uk/uksi/2006/214/schedule/3/paragraph/1
+    - title: The Social Security Benefits Up-rating Order 2026 article 24(6) and Schedule 6
+      href: https://www.legislation.gov.uk/uksi/2026/148/schedule/6/made
     - title: Benefit and pension rates 2024 to 2025 - Policy paper
       href: https://www.gov.uk/government/publications/benefit-and-pension-rates-2024-to-2025/benefit-and-pension-rates-2024-to-2025
     - title: Benefit and pension rates 2020 to 2021 (DWP, gov.uk)
@@ -33,3 +49,5 @@ metadata:
       href: https://www.legislation.gov.uk/uksi/2025/295/contents/made
     - title: The Social Security Benefits Up-rating Order 2026 (SI 2026/148)
       href: https://www.legislation.gov.uk/uksi/2026/148/contents/made
+    - title: A14/2025 Housing Benefit uprating for the financial year ending March 2027, paragraphs 5 and 20
+      href: https://www.gov.uk/government/publications/housing-benefit-adjudication-circulars-2025/a142025-housing-benefit-uprating-for-the-financial-year-ending-march-2027
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		- Corrects the Pension Credit standard minimum guarantee projection to follow the statutory May-July earnings input with a non-negative floor.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		- Corrected the 2025-26 Pension Credit rates and derived future Savings Credit thresholds from the earnings-projected guarantee and CPI-projected maximum without replacing explicit or reformed threshold values.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		- Correct the 2025-26 rates and forecast basis for protected single, lone-parent, and couple pension-age Housing Benefit personal allowances.