MaxGhenis · Oct 2, 2026 · Sep 30, 2026 · Sep 30, 2026
diff --git a/changelog.d/1879.fixed.md b/changelog.d/1879.fixed.md
@@ -0,0 +1 @@
+- Hold the NICs primary threshold, upper earnings limit, secondary threshold and Class 4 lower and upper profits limits at their 2026-27 levels through 2030-31, as announced at Budget 2025, with a reference for each year. CPI uprating resumes in 2031-32; before this change the Class 4 limits were uprated from 2027-28 and the primary threshold and upper earnings limit from 2028-29. Also correct the 2025-26 lower earnings limit to £125 a week (SI 2025/288).
diff --git a/docs/book/policy/model-baseline.md b/docs/book/policy/model-baseline.md
@@ -4,6 +4,12 @@
 PolicyEngine UK models the UK tax and benefit system as of 2025, incorporating major reforms from 2020-2025. This page documents the key policy changes by year, working backwards from 2025, showing how each reform is implemented in the codebase.
 ```
 
+## Announced policy to 2030-31
+
+### Budget 2025 threshold freezes
+
+Budget 2025 keeps the income tax personal allowance and basic rate limit, and the equivalent National Insurance thresholds, at their current levels until April 2031. The model holds the [primary threshold](https://github.com/PolicyEngine/policyengine-uk/blob/main/policyengine_uk/parameters/gov/hmrc/national_insurance/class_1/thresholds/primary_threshold.yaml) and [lower profits limit](https://github.com/PolicyEngine/policyengine-uk/blob/main/policyengine_uk/parameters/gov/hmrc/national_insurance/class_4/thresholds/lower_profits_limit.yaml) at £12,570, the [upper earnings limit](https://github.com/PolicyEngine/policyengine-uk/blob/main/policyengine_uk/parameters/gov/hmrc/national_insurance/class_1/thresholds/upper_earnings_limit.yaml) and [upper profits limit](https://github.com/PolicyEngine/policyengine-uk/blob/main/policyengine_uk/parameters/gov/hmrc/national_insurance/class_4/thresholds/upper_profits_limit.yaml) at £50,270, and the [secondary threshold](https://github.com/PolicyEngine/policyengine-uk/blob/main/policyengine_uk/parameters/gov/hmrc/national_insurance/class_1/thresholds/secondary_threshold.yaml) at £96 a week through 2030-31, then uprates them with CPI from 2031-32. For Class 1, regulations set only the 2026-27 amounts; the later years are announced policy. The Class 4 limits are standing figures in SSCBA 1992 s.15(3). The model annualises the weekly secondary threshold as 52 × £96 = £4,992; the annual figure in law is £5,000 ([#1967](https://github.com/PolicyEngine/policyengine-uk/issues/1967)). The [lower earnings limit](https://github.com/PolicyEngine/policyengine-uk/blob/main/policyengine_uk/parameters/gov/hmrc/national_insurance/class_1/thresholds/lower_earnings_limit.yaml) is not frozen: it rose with CPI to £129 a week in 2026-27.
+
 ## 2025 reforms
 
 ### Autumn Budget 2024

diff --git a/...ne_uk/parameters/gov/hmrc/national_insurance/class_1/thresholds/lower_earnings_limit.yaml b/...ne_uk/parameters/gov/hmrc/national_insurance/class_1/thresholds/lower_earnings_limit.yaml
@@ -8,6 +8,8 @@ metadata:
   unit: currency-GBP
   uprating: gov.economic_assumptions.indices.obr.consumer_price_index
   label: NI lower earnings limit
+# The LEL is not frozen: Budget 2025 para 4.118 raised it by September 2025 CPI
+# for 2026-27. Values from 2027-28 are a CPI projection; none is announced.
 values:
   2015-04-06: 112
   2016-04-06: 112
@@ -23,9 +25,17 @@ values:
         title: The Social Security (Contributions) (Rates, Limits and Thresholds Amendments
           and National Insurance Funds Payments) Regulations 2022(6)
     value: 123
+  2025-04-06:
+    value: 125
+    metadata:
+      reference:
+        - title: SI 2025/288 reg 5(2)(b), amending SI 2001/1004 reg 10(a)
+          href: https://www.legislation.gov.uk/uksi/2025/288/regulation/5/made
   2026-04-06:
     value: 129
     metadata:
       reference:
-        - title: "GOV.UK | Rates and allowances: National Insurance contributions"
-          href: https://www.gov.uk/government/publications/rates-and-allowances-national-insurance-contributions/rates-and-allowances-national-insurance-contributions
+        - title: SI 2026/231 reg 5(2)(b), amending SI 2001/1004 reg 10(a)
+          href: https://www.legislation.gov.uk/uksi/2026/231/regulation/5/made
+        - title: Budget 2025 (HC 1492) para 4.118
+          href: https://assets.publishing.service.gov.uk/media/6929b353345e31ab14ecf735/E03444720_Budget_2025_Web_Accessible.pdf#page=114
diff --git a/...ngine_uk/parameters/gov/hmrc/national_insurance/class_1/thresholds/primary_threshold.yaml b/...ngine_uk/parameters/gov/hmrc/national_insurance/class_1/thresholds/primary_threshold.yaml
@@ -1,4 +1,12 @@
 description: The Primary Threshold is the lower bound for the main rate of Class 1 National Insurance.
+# From 6 July 2022 the model stores the annual earnings period threshold
+# divided by 52 (12,570 / 52, rounded to 241.73), as SI 2001/1004 reg 11(3)(c)
+# does for periods of whole weeks; 52 weeks give £12,569.96. The weekly amount
+# in reg 10(c) is £242.
+# Legal status: SI 2001/1004 reg 10 sets the amounts for 2026-27 only. The
+# 2027-28 to 2030-31 values are announced policy (Autumn Statement 2022 and
+# Budget 2025), to be set in each year's rates, limits and thresholds
+# regulations. CPI uprating from 2031-32 is a modelling assumption.
 values:
   2015-04-06: 155
   2016-04-06: 155
@@ -13,18 +21,56 @@ values:
       reference:
         - title: The Social Security (Contributions) (Rates, Limits and Thresholds Amendments and National Insurance Funds Payments) Regulations 2022(6)
           href: https://www.legislation.gov.uk/uksi/2022/232/regulation/6/made#regulation-6-2-a
-  2022-07-01: 
+  2022-07-01:
     value: 241.73
     metadata:
       reference:
         - title: Spring Statement 2022
           href: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1062486/Spring_Statement_2022_Web_Accessible.pdf
-  2027-04-01: 
+  2026-04-06:
     value: 241.73
     metadata:
       reference:
-        - title: Spring Statement 2022
-          href: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1062486/Spring_Statement_2022_Web_Accessible.pdf
+        - title: The Social Security (Contributions) Regulations 2001 reg 10(c) and reg 11(3), for 2026-27 (reg 10's tax year set by SI 2026/231 reg 5(2)(a))
+          href: https://www.legislation.gov.uk/uksi/2001/1004/regulation/11/2026-04-06
+        - title: SI 2026/231 reg 5
+          href: https://www.legislation.gov.uk/uksi/2026/231/regulation/5/made
+  2027-04-06:
+    value: 241.73
+    metadata:
+      reference:
+        - title: "HMRC: Income Tax Personal Allowance and the basic rate limit, and certain National Insurance contributions thresholds from 6 April 2026 to 5 April 2028 (Autumn Statement 2022)"
+          href: https://www.gov.uk/government/publications/the-personal-allowance-and-basic-rate-limit-for-income-tax-and-certain-national-insurance-contributions-nics-thresholds-from-6-april-2026-to-5-apr/income-tax-personal-allowance-and-the-basic-rate-limit-and-certain-national-insurance-contributions-thresholds-from-6-april-2026-to-5-april-2028
+  2028-04-06:
+    value: 241.73
+    metadata:
+      reference:
+        - title: Budget 2025 (HC 1492) para 4.111
+          href: https://assets.publishing.service.gov.uk/media/6929b353345e31ab14ecf735/E03444720_Budget_2025_Web_Accessible.pdf#page=113
+        - title: "HMRC: Maintaining Income Tax and equivalent National Insurance contributions thresholds until 5 April 2031"
+          href: https://www.gov.uk/government/publications/maintaining-income-tax-and-equivalent-national-insurance-contributions-thresholds-until-5-april-2031/income-tax-maintaining-the-personal-allowance-and-the-basic-rate-limit-for-income-tax-and-equivalent-national-insurance-contributions-thresholds-unt
+        - title: Explanatory Memorandum to SI 2026/231 para 5.25
+          href: https://www.legislation.gov.uk/uksi/2026/231/pdfs/uksiem_20260231_en_001.pdf
+  2029-04-06:
+    value: 241.73
+    metadata:
+      reference:
+        - title: Budget 2025 (HC 1492) para 4.111
+          href: https://assets.publishing.service.gov.uk/media/6929b353345e31ab14ecf735/E03444720_Budget_2025_Web_Accessible.pdf#page=113
+        - title: "HMRC: Maintaining Income Tax and equivalent National Insurance contributions thresholds until 5 April 2031"
+          href: https://www.gov.uk/government/publications/maintaining-income-tax-and-equivalent-national-insurance-contributions-thresholds-until-5-april-2031/income-tax-maintaining-the-personal-allowance-and-the-basic-rate-limit-for-income-tax-and-equivalent-national-insurance-contributions-thresholds-unt
+        - title: Explanatory Memorandum to SI 2026/231 para 5.25
+          href: https://www.legislation.gov.uk/uksi/2026/231/pdfs/uksiem_20260231_en_001.pdf
+  2030-04-06:
+    value: 241.73
+    metadata:
+      reference:
+        - title: Budget 2025 (HC 1492) para 4.111
+          href: https://assets.publishing.service.gov.uk/media/6929b353345e31ab14ecf735/E03444720_Budget_2025_Web_Accessible.pdf#page=113
+        - title: "HMRC: Maintaining Income Tax and equivalent National Insurance contributions thresholds until 5 April 2031"
+          href: https://www.gov.uk/government/publications/maintaining-income-tax-and-equivalent-national-insurance-contributions-thresholds-until-5-april-2031/income-tax-maintaining-the-personal-allowance-and-the-basic-rate-limit-for-income-tax-and-equivalent-national-insurance-contributions-thresholds-unt
+        - title: Explanatory Memorandum to SI 2026/231 para 5.25
+          href: https://www.legislation.gov.uk/uksi/2026/231/pdfs/uksiem_20260231_en_001.pdf
 metadata:
   label: NI primary threshold
   unit: currency-GBP

diff --git a/...ine_uk/parameters/gov/hmrc/national_insurance/class_1/thresholds/secondary_threshold.yaml b/...ine_uk/parameters/gov/hmrc/national_insurance/class_1/thresholds/secondary_threshold.yaml
@@ -7,6 +7,12 @@ metadata:
   - https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/882271/Table-a4.pdf
   - https://www.gov.uk/government/publications/rates-and-allowances-national-insurance-contributions/rates-and-allowances-national-insurance-contributions
   unit: currency-GBP
+# The model stores the weekly £96 in reg 10(d) and annualises it as 52 weeks
+# (£4,992); reg 11(3A)(b) gives £5,000 a year (#1967).
+# Legal status: SI 2001/1004 reg 10 sets the amounts for 2026-27 only. The
+# 2027-28 to 2030-31 values are announced policy (Autumn Budget 2024 and
+# Budget 2025), to be set in each year's rates, limits and thresholds
+# regulations. CPI uprating from 2031-32 is a modelling assumption.
 values:
   2015-04-06: 155
   2016-04-06: 155
@@ -23,19 +29,47 @@ values:
           and National Insurance Funds Payments) Regulations 2022(6)
     value: 175
   2024-01-01: 175
-  2025-01-01: 
+  2025-04-06:
     value: 96
-    reference:
-      - title: National Insurance Contributions (Secondary Class 1 Contributions) Act 2025(2)
-        href: https://www.legislation.gov.uk/ukpga/2025/11/section/2
-  2027-01-01:
+    metadata:
+      reference:
+        - title: National Insurance Contributions (Secondary Class 1 Contributions) Act 2025 s.2
+          href: https://www.legislation.gov.uk/ukpga/2025/11/section/2
+  2026-04-06:
     value: 96
-    reference:
-      - title: National Insurance Contributions (Secondary Class 1 Contributions) Act 2025(2)
-        href: https://www.legislation.gov.uk/ukpga/2025/11/section/2
+    metadata:
+      reference:
+        - title: The Social Security (Contributions) Regulations 2001 reg 10(d) and reg 11(3A), for 2026-27 (reg 10's tax year set by SI 2026/231 reg 5(2)(a))
+          href: https://www.legislation.gov.uk/uksi/2001/1004/regulation/11/2026-04-06
+        - title: SI 2026/231 reg 5
+          href: https://www.legislation.gov.uk/uksi/2026/231/regulation/5/made
+  2027-04-06:
+    value: 96
+    metadata:
+      reference:
+        - title: "HMRC: Changes to the Class 1 National Insurance Contributions Secondary Threshold, the Secondary Class 1 National Insurance contributions rate, and the Employment Allowance from 6 April 2025 (Autumn Budget 2024)"
+          href: https://www.gov.uk/government/publications/changes-to-the-class-1-national-insurance-contributions-secondary-threshold-the-secondary-class-1-national-insurance-contributions-rate-and-the-empl/changes-to-the-class-1-national-insurance-contributions-secondary-threshold-the-secondary-class-1-national-insurance-contributions-rate-and-the-empl
+  2028-04-06:
+    value: 96
+    metadata:
+      reference:
+        - title: Budget 2025 (HC 1492) para 4.112
+          href: https://assets.publishing.service.gov.uk/media/6929b353345e31ab14ecf735/E03444720_Budget_2025_Web_Accessible.pdf#page=113
+        - title: Explanatory Memorandum to SI 2026/231 para 5.26
+          href: https://www.legislation.gov.uk/uksi/2026/231/pdfs/uksiem_20260231_en_001.pdf
+  2029-04-06:
+    value: 96
+    metadata:
+      reference:
+        - title: Budget 2025 (HC 1492) para 4.112
+          href: https://assets.publishing.service.gov.uk/media/6929b353345e31ab14ecf735/E03444720_Budget_2025_Web_Accessible.pdf#page=113
+        - title: Explanatory Memorandum to SI 2026/231 para 5.26
+          href: https://www.legislation.gov.uk/uksi/2026/231/pdfs/uksiem_20260231_en_001.pdf
   2030-04-06:
     value: 96
     metadata:
       reference:
-        - title: OBR Economic and Fiscal Outlook November 2025
-          href: https://obr.uk/efo/economic-and-fiscal-outlook-november-2025/
+        - title: Budget 2025 (HC 1492) para 4.112
+          href: https://assets.publishing.service.gov.uk/media/6929b353345e31ab14ecf735/E03444720_Budget_2025_Web_Accessible.pdf#page=113
+        - title: Explanatory Memorandum to SI 2026/231 para 5.26
+          href: https://www.legislation.gov.uk/uksi/2026/231/pdfs/uksiem_20260231_en_001.pdf
diff --git a/...ne_uk/parameters/gov/hmrc/national_insurance/class_1/thresholds/upper_earnings_limit.yaml b/...ne_uk/parameters/gov/hmrc/national_insurance/class_1/thresholds/upper_earnings_limit.yaml
@@ -1,4 +1,12 @@
 description: The Upper Earnings Limit is the upper bound for the main rate of Class 1 National Insurance.
+# From 2021-22 the model stores the annual earnings period limit divided by 52
+# (50,270 / 52, rounded to 966.73), as SI 2001/1004 reg 11(2A)(c) does for
+# periods of whole weeks; 52 weeks give £50,269.96. The weekly amount in
+# reg 10(b) is £967.
+# Legal status: SI 2001/1004 reg 10 sets the amounts for 2026-27 only. The
+# 2027-28 to 2030-31 values are announced policy (Autumn Statement 2022 and
+# Budget 2025), to be set in each year's rates, limits and thresholds
+# regulations. CPI uprating from 2031-32 is a modelling assumption.
 values:
   2015-04-06: 815
   2016-04-06: 827
@@ -7,7 +15,50 @@ values:
   2019-04-06: 962
   2020-04-06: 962
   2021-04-06: 966.73
-  2027-04-06: 966.73
+  2026-04-06:
+    value: 966.73
+    metadata:
+      reference:
+        - title: The Social Security (Contributions) Regulations 2001 reg 10(b) and reg 11(2A), for 2026-27 (reg 10's tax year set by SI 2026/231 reg 5(2)(a))
+          href: https://www.legislation.gov.uk/uksi/2001/1004/regulation/11/2026-04-06
+        - title: SI 2026/231 reg 5
+          href: https://www.legislation.gov.uk/uksi/2026/231/regulation/5/made
+  2027-04-06:
+    value: 966.73
+    metadata:
+      reference:
+        - title: "HMRC: Income Tax Personal Allowance and the basic rate limit, and certain National Insurance contributions thresholds from 6 April 2026 to 5 April 2028 (Autumn Statement 2022)"
+          href: https://www.gov.uk/government/publications/the-personal-allowance-and-basic-rate-limit-for-income-tax-and-certain-national-insurance-contributions-nics-thresholds-from-6-april-2026-to-5-apr/income-tax-personal-allowance-and-the-basic-rate-limit-and-certain-national-insurance-contributions-thresholds-from-6-april-2026-to-5-april-2028
+  2028-04-06:
+    value: 966.73
+    metadata:
+      reference:
+        - title: Budget 2025 (HC 1492) para 4.111
+          href: https://assets.publishing.service.gov.uk/media/6929b353345e31ab14ecf735/E03444720_Budget_2025_Web_Accessible.pdf#page=113
+        - title: "HMRC: Maintaining Income Tax and equivalent National Insurance contributions thresholds until 5 April 2031"
+          href: https://www.gov.uk/government/publications/maintaining-income-tax-and-equivalent-national-insurance-contributions-thresholds-until-5-april-2031/income-tax-maintaining-the-personal-allowance-and-the-basic-rate-limit-for-income-tax-and-equivalent-national-insurance-contributions-thresholds-unt
+        - title: Explanatory Memorandum to SI 2026/231 para 5.25
+          href: https://www.legislation.gov.uk/uksi/2026/231/pdfs/uksiem_20260231_en_001.pdf
+  2029-04-06:
+    value: 966.73
+    metadata:
+      reference:
+        - title: Budget 2025 (HC 1492) para 4.111
+          href: https://assets.publishing.service.gov.uk/media/6929b353345e31ab14ecf735/E03444720_Budget_2025_Web_Accessible.pdf#page=113
+        - title: "HMRC: Maintaining Income Tax and equivalent National Insurance contributions thresholds until 5 April 2031"
+          href: https://www.gov.uk/government/publications/maintaining-income-tax-and-equivalent-national-insurance-contributions-thresholds-until-5-april-2031/income-tax-maintaining-the-personal-allowance-and-the-basic-rate-limit-for-income-tax-and-equivalent-national-insurance-contributions-thresholds-unt
+        - title: Explanatory Memorandum to SI 2026/231 para 5.25
+          href: https://www.legislation.gov.uk/uksi/2026/231/pdfs/uksiem_20260231_en_001.pdf
+  2030-04-06:
+    value: 966.73
+    metadata:
+      reference:
+        - title: Budget 2025 (HC 1492) para 4.111
+          href: https://assets.publishing.service.gov.uk/media/6929b353345e31ab14ecf735/E03444720_Budget_2025_Web_Accessible.pdf#page=113
+        - title: "HMRC: Maintaining Income Tax and equivalent National Insurance contributions thresholds until 5 April 2031"
+          href: https://www.gov.uk/government/publications/maintaining-income-tax-and-equivalent-national-insurance-contributions-thresholds-until-5-april-2031/income-tax-maintaining-the-personal-allowance-and-the-basic-rate-limit-for-income-tax-and-equivalent-national-insurance-contributions-thresholds-unt
+        - title: Explanatory Memorandum to SI 2026/231 para 5.25
+          href: https://www.legislation.gov.uk/uksi/2026/231/pdfs/uksiem_20260231_en_001.pdf
 metadata:
   label: NI upper earnings limit
   unit: currency-GBP
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		- Hold the NICs primary threshold, upper earnings limit, secondary threshold and Class 4 lower and upper profits limits at their 2026-27 levels through 2030-31, as announced at Budget 2025, with a reference for each year. CPI uprating resumes in 2031-32; before this change the Class 4 limits were uprated from 2027-28 and the primary threshold and upper earnings limit from 2028-29. Also correct the 2025-26 lower earnings limit to £125 a week (SI 2025/288).