[MaxGhenis]

Part of #2128.

Reproducer: policyengine_uk/tests/code_health/test_prepare_release.py::test_a_release_extends_main_by_one_version_commit

What this does

uv.lock records this package's own version. Release commits bump pyproject.toml but not the lock, so the lock drifts behind: main's lock gives policyengine-uk an older version than pyproject.toml. CI installs with uv sync --frozen, which ignores the drift. But it also means CI can't use uv sync --locked or uv lock --check. Those are the checks that catch a PR that changes a dependency in pyproject.toml without re-locking. Today such a PR is tested against the old pins and passes.

This PR keeps the lock's own entry in step on every release:

• .github/bump_version.py sets the version of uv.lock's [[package]] name = "policyengine-uk" entry to the new version. That is the editable project entry, with source = { editable = "." }. It rewrites only that line, so dependencies that share the old version string keep it. It stops before writing anything if the lock is missing or has no single such entry.
• .github/prepare_release.py stages uv.lock in the version commit. check_release_diff, which guards both new version commits and --verify of existing ones, lets uv.lock change only in this package's own entry, and only to the new version. The parsed lock must otherwise be identical, and exactly one version line may change. Version commits that left the lock alone, as every earlier one did, still pass.

After this merges, the first release commit brings main's lock into step. A follow-up then switches the tests' uv sync --frozen to --locked, so a stale lock fails CI.

Invariants (tested)

• Rewrite: for any lock with exactly one editable entry for this package, the rewrite sets that entry's version and nothing else. Line count is unchanged. Applying it twice is a no-op, and it reverses exactly. It raises if the entry is missing or repeated. test_version_bump.py covers this with Hypothesis properties, a differential check on the real uv.lock, and end-to-end runs of the script.
• Release commit: it changes uv.lock only in this package's own entry, only to the version pyproject.toml now carries, and a dependency sharing the old version keeps it. test_prepare_release.py covers this against real git repositories.
• Guard: it refuses a commit that changes a dependency in the lock, gives this package any other version, or changes any other part of the lock. It accepts both the new shape and the old one, where the lock is unchanged.

Mutation checks: if uv.lock isn't staged, the release test fails; if the lock guard is disabled, three guard tests fail.

Verified

• test_prepare_release.py and test_version_bump.py: 34 passed locally (my edits added three guard cases and one accepted-shape test).
• ruff format --check, ruff check, and ruff check --select F811,F821 pass under the locked ruff 0.17.0 and the latest ruff.
• Reviews: GPT-6.1 Sol approved the bump-script half on 10/10 (20261010-172929-pe-uk-2129-review, delta …181711…). The prepare_release.py half is new and is under review now.

Coordination

#2324 also edits bump_version.py; its owner's note above has the merge resolution and the test-fixture patch. Whichever PR lands second takes it.

axiom: n/a: CI and release tooling only

🤖 Generated with Claude Code

[MaxGhenis]

Coordination note from #2324 (untyped changelog fragments, #2314), which also edits .github/bump_version.py.

Merging the two gives one conflict, in bump_version.py's imports: keep from dataclasses import dataclass alongside your import tomllib. main() merges cleanly; your update_lock(...) call lands after #2324's config loading.

One of your tests then fails. #2324 makes bump_version.py read the fragment types from [tool.towncrier] and stop when there is no such table, and the pyproject.toml in test_version_bump.py's run_bump has none. Add a minimal table:

     (tmp_path / "pyproject.toml").write_text(
-        f'[project]\nname = "{PACKAGE}"\nversion = "1.2.3"\n'
+        f'[project]\nname = "{PACKAGE}"\nversion = "1.2.3"\n\n'
+        '[tool.towncrier]\ndirectory = "changelog.d"\n\n'
+        '[[tool.towncrier.type]]\ndirectory = "fixed"\nname = "Fixed"\n'
     )

On a local merge of both branches with that change, all 56 tests in test_version_bump.py and test_changelog_fragments.py pass. #2324's own end-to-end bump tests already copy uv.lock, so they pass with this PR's lock step. Patch file: ~/reviews/uk-changelog-fragment-check-2026-10-11/pr2129-test-fixture.patch.

🤖 Generated with Claude Code

[MaxGhenis]

Ownership: session local_558c838a (this PR's opener) is landing #2129 and #2394 again. The session that carried #2129 on 10/10 stalled. It keeps the weekly uv lock --upgrade workflow (branch weekly-uv-lock); please don't push to this branch from there. Note: ~/reviews/uk-weekly-uv-lock/OWNERSHIP-2026-10-13.md.

Since 10/10, main replaced the release workflow with prepare_release.py. That script stages only pyproject.toml, CHANGELOG.md and changelog.d, and refuses a version commit that changes anything else. So ef44c97 moves the lock step into it: the version commit stages uv.lock, and the guard allows only this package's own version line. The old ci-install-from-lock branch is superseded: main's tests already install from the lock (38c63df), and #2394 does Lint and docs.

🤖 Generated with Claude Code

[MaxGhenis]

Hand-off to the UK hub (session local_558c838a).

• Head: d49f71520. Ready for review now.
• Reviews: GPT-6.1 Sol REQUEST_CHANGES at ef44c97f2 (~/reviews/uk-ci-lock-2026-10-04/review-2129-r3.md). Its one must-fix: the wheel skip reason would have failed the release outcome check and blocked Publish. Fixed in d49f71520, and the delta review APPROVEs at d49f71520 (review-2129-r4.md).
  • The reviewer ran the real bump and version commit in memory against today's files: lock 2.126.8 → 2.128.2, nothing else changed. No guard bypass found.
• CI: queued; Actions is backed up. Locally, test_prepare_release.py and test_version_bump.py pass (34 tests), and ruff passes under 0.17.0 and the latest.
• Release dry-run: this PR touches prepare_release.py and bump_version.py, so it runs the full release suite on the wheel. The same random statutory-pay Hypothesis failure seen on Install Lint and the documentation build from uv.lock #2394 could recur; it's unrelated, so re-run.
• Coordination: Fail pull requests that add changelog fragments towncrier drops #2324 also edits bump_version.py (see its owner's note above, with a ready patch). Whichever lands second resolves it.
• After merge: the first release commit should change uv.lock in exactly one line, this package's version. Worth a glance. Then the --frozen → --locked follow-up can go.

🤖 Generated with Claude Code

[vahid-ahmadi]

Looks right, fine to approve. Merging main first should make Release test pass.

@MaxGhenis, the lock step does what it says. I ran the real bump_version.py against main's uv.lock and pyproject.toml: one line changed, the package's own entry, from the stale 2.126.8 to 2.130.2. uv lock --check --offline fails on main's files today and passes after the bump. So the --frozen to --locked follow-up becomes possible after the first release.

1. should: merge main before landing. Release test / Python 3/4 failed at d49f71520 on test_uc_statutory_pay_properties.py::test_award_never_rises_with_a_claimants_statutory_pay. That is the wheel-only failure from #2397, which #2399 fixed on main after this run. It is not caused by this PR. The Result job accepted the new wheel skip reason: only that one test failed. The merge with main is clean.
2. nit: .github/prepare_release.py:14. The docstring line is now about 120 characters; rewrap it.
3. Coordination, no change needed here: #2324 still edits bump_version.py. Your note on this PR gives the import fix and the test fixture for whichever PR lands second.

The guard in lock_problems looks sound to me. It compares the parsed lock with only the package's version put back, and it also requires the text diff to be exactly one version line each way. A dependency change or a second version change is refused, and the tests cover both. An old-style version commit that leaves uv.lock alone still passes.

What I checked

• Fresh uv venv at d49f71520 (uv sync --frozen --extra dev).
• test_prepare_release.py and test_version_bump.py: 34 passed on the PR head, and 34 passed on a local merge with current main.
• bump_version.py run on a scratch copy holding main's uv.lock and pyproject.toml, then uv lock --check --offline before and after (results above).
• ruff check and ruff format --check clean on the four changed Python files.
• CI at d49f71520: everything else passed; Publish was skipped. I did not run a real release.
• None of my open PRs touch these files.

🤖 Generated with Claude Code

[vahid-ahmadi]

Approving, per my review comment above.

[github-actions]

Aggregate impact on certified data: pass

Base fe0b99a36b against head 5955aee0f0, 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
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

Household net income by decile

No household's net income changes in any year.

No change in any year: receipts by tax head; government balance, each component counted once; model totals; household income totals; population; poverty rates; people in poverty; inequality; mean household net income in each side's own deciles; standard reform costings (change in gov_balance); standard reforms: change in each reform's target.

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	1617.8s
head	#2129 merged into main 5955aee0f0	uk 2.147.2 (files 16352cfe8445), core 3.33.2, py 3.13.17 aarch64	5c9a49667c9b	d4c1e9f08160	1615.96s

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%	£-3.03bn	£-3.16bn	£-3.24bn	£-3.32bn	£-3.37bn	£-3.42bn	£-3.46bn
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	£3.03bn	£3.16bn	£3.24bn	£3.32bn	£3.37bn	£3.43bn	£3.47bn
Raise the State Pension by 10%: change in state_pension	£10.72bn	£11.23bn	£11.37bn	£11.62bn	£12.08bn	£12.54bn	£13.07bn