A different economy.
Your decisions.

All results are changes from a reference policy with monetary scales held fixed. GDP uses £3,097.533bn (the latest four ONS quarters); household figures use 29.0m households. These releases cover different periods; their values are held fixed without an inflation rebasing step. Year 1 means the first year of your package, not a calendar forecast. The chart shows a GDP-level difference, not annual growth.

Taxes and investment continue annually. Surpluses reduce borrowing. Unfunded cuts or spending increase it. We include a 35% tax feedback from GDP and a separate rate-sensitive interest calculation. The 4% reference financing rate is a modelling assumption, not a current market quote.

We run cautious, central and optimistic assumptions and show the smallest and largest result for each metric. Outcomes outside these bounds are possible. The endpoints are neither probabilities nor confidence limits.

Wealth-tax revenue varies around the campaign anchor by 0.65× / 1× / 1.1×. CGT uses two separate policy costings. The higher-rate rise uses HMRC’s three annual estimates, holding the last constant afterwards. Full reform uses CenTax’s £11.3bn annual estimate from year 1. These timing assumptions are ours; neither is a published ten-year forecast. The scenario envelope does not measure CGT costing uncertainty. Supply and demand responses vary separately. The model omits a full inflation forecast, monetary feedback to demand, population changes, land-price adjustment and detailed policy interactions.

Initial demand multipliers are 0.3 for income tax/NI, 0.35 for VAT/fuel, 0.1 for other taxes, 1 for investment, 0.4 for repayments avoided and 0.5 for domestic stimulus. Responses vary by 0.6× / 1× / 1.4× and fade to zero by year 5.

At year 10 the central supply assumptions, in percentage points of GDP, are: +0.04 per point cut to basic income tax or employee NI; +0.015 higher-rate; +0.045 employer NI; +0.035 corporation tax; +0.1 per point of land tax; +0.025 per £1bn annual investment. Wealth-tax drag is −0.08 per rate point (40% of that for the billionaire floor). These are toy coefficients, not sourced causal estimates.

EU entry is assumed in year 3. By year 10, GDP gains range from 0% to 4.2% (central 2%), with £10–18bn annual net contributions. Rejoining does not automatically reverse the estimated costs of Brexit.

Student forgiveness cancels existing UK income-contingent loans. SLC reports £324.8bn face value; annual net repayments sum to £6.0251bn. Using those receipts as repayments forgone is a proxy. The £200bn recoverable asset loss and 6% annual repayment decline are assumptions. The asset loss is shown separately from cash borrowing. The £1,000 cheque is paid only in year 1 to all assumed citizens, including those overseas; 92% is allocated to domestic households.

The household view divides households into equal income fifths. We assign each tax and transfer an explicit set of shares, rather than pretending to use household microdata. Wealth and income ranks are not the same.

Half of the GDP change flows into household income. CGT household effects are not estimated. Other direct tax effects reach households except corporation tax (50%) and employer NI (26% in year 1, rising to 80% in year 10). Income-side effects, living costs, asset taxes and economic assumptions are shown separately. Public services, asset-price changes and debt balances are not counted as household income. Exact weights and equations are included in the downloadable model notes.

The 2026/27 main rates are basic/higher income tax 20%/40%, employee/employer NI 8%/15%, corporation tax 25%/19%, VAT 20%, CGT 18%/24% and dividends 10.75%/35.75%. These are the rates represented by the toy, not a full tax system. Devolved bands, thresholds, relief details and future scheduled changes are not separately modelled. HMRC revenue sensitivities still reflect the older June 2025 publication.

Dividend alignment responds to your income-tax settings. CGT choices have fixed rates and revenue anchors; changing income-tax sliders does not switch them off or recost them. Combining these policies adds their standalone costings; interactions are not modelled. The billionaire floor credits an assumed share of dividends and land tax, and replaces the annual wealth levy. Land tax is additional to existing property taxes. Large packages exceed the reliable scope of simple HMRC ready-reckoner arithmetic.

Unemployment moves by −0.3 percentage points per 1% cyclical demand gap in the central case (range −0.2 to −0.4). We hold the ONS labour force of 36.241m fixed and assume £8,000 benefits per additional unemployed person. The response fades by year 5 as demand normalises. Long-run productivity gains alone do not create a permanent fall in unemployment.

The £1,360.122bn spending reference is Treasury’s first 2025/26 outturn. Every baseline slice comes from Table 5.2. Debt interest & transactions includes Bank and pension flows; Other includes accounting adjustments. This is Total Managed Expenditure, not purely cash spending. Only explicit spending policies, unemployment benefits and interest change the pie.

Central Bank Rate change = your reaction coefficient × the demand gap, plus 25bp per percentage point of a first-year VAT inflation impulse (assumed 0.3 points per VAT-rate point). Supply-led growth does not automatically trigger rate increases.

The ten-year gilt change is average expected Bank Rate change plus a premium on projected extra debt/GDP plus your market shock. Existing gilt coupons stay fixed; 1/14 of a £2tn stock refinances each year. £500bn is assumed exposed to Bank Rate. New borrowing uses a 4% reference yield plus the gilt change. These inputs simplify the debt book and exclude inflation-linked debt effects.