UC standard allowance omits the legislated 2027-28 to 2029-30 uplifts; standard_allowance_uplift is never read #2239

What happens

parameters/gov/dwp/universal_credit/rebalancing/standard_allowance_uplift.yaml holds the Universal Credit Act 2025 uplifts above inflation: 2.3% for 2026, 3.1% for 2027, 4.0% for 2028 and 4.8% for 2029, relative to 2025-26 levels. No formula reads it:

• uc_standard_allowance uses standard_allowance.amount only (variables/gov/dwp/universal_credit/standard_allowance/uc_standard_allowance.py).
• amount.yaml has values to 2026-04-01 (£424.90 for a single person aged 25 or over, which includes the 2026 uplift) and plain CPI uprating after that.

A code search on main finds the parameter only in the docs.

Reproducer

Run at 2.89.2. On main as of 9 October 2026, amount.yaml still ends at 2026-04-01.

A single claimant aged 30. Annual uc_standard_allowance: 2025 £4,801.68; 2026 £5,098.80; 2027 £5,216.06 (+2.3%, CPI only); 2028 £5,320.37; 2029 £5,426.78; 2030 £5,535.30.

Impact

Found by the fiscal-event replay in PolicyEngine/policyengine-scorecard#157. Spring Statement 2025's standard allowance increase costs at most £0.49bn a year in PolicyEngine, against the OBR's £1.55bn. The certified world lacks the 2027 to 2029 uplifts, so the reform's difference stays flat. The law is the Universal Credit Act 2025 s.1.

Fix

Apply the uplift in the amount's uprating, or in uc_standard_allowance, from 2027, and add tests for 2027-28 to 2029-30 against the Act's figures.