UK fiscal headroom halves to £11bn and may fall to a £7bn deficit

EY UK Pre-Budget Fiscal Outlook - October 2026

The £11.3bn estimate draws on the EY UK Economic Outlook's baseline forecast, which assumes the Strait of Hormuz reopens around the end of Q3 2026, albeit with subdued tanker traffic. However, under EY’s adverse scenario – where the Strait remains closed into early or mid-2027 and UK inflation reaches 6% by the end of 2026 – weaker growth, rising unemployment, elevated borrowing costs and falling equity prices would reduce headroom by a further £18bn, turning the £11.3bn surplus into a deficit of around £7bn.

Peter Arnold, EY UK Chief Economist, said: “While £11bn sounds substantial, it amounts to around 1% of total tax receipts, leaving the public finances with very little margin for error. On margins this fine, relatively modest shifts in growth, inflation or gilt yields can move the fiscal position by billions. A prolonged conflict in the Middle East would be enough to erase the headroom altogether, which would put the Government on course to miss its fiscal rule.

“Over the past six months, headroom has eroded by more than half, underscoring how much of the fiscal position can be shaped by external economic factors rather than domestic policy. Under these conditions, tax and spending decisions can only achieve so much and ultimately growth remains the key swing factor in building strong public finances that can lift receipts, ease fiscal pressure and unlock the funding for national priorities.”

Fiscal projections remain highly sensitive to economic outturns

EY's analysis highlights how finely balanced UK public finances are, with relatively small changes in the economic outlook having an outsized effect on the UK’s fiscal position.

The reduction in headroom since March is a result of a weaker economy and a more uncertain global outlook. EY analysis identifies rising gilt yields as the single largest drag, expected to have reduced headroom by £10bn by increasing debt servicing costs, while elevated inflation has pushed up market expectations that interest rates will remain higher for longer. Rising unemployment has also weighed on tax receipts and increased welfare spending.

Under EY's adverse scenario, headroom is reduced by a further 18bn relative to the EY baseline, falling to a deficit of £7bn and therefore missing the fiscal rule. The largest single driver is expected to be a fall in equity prices, which would reduce receipts from capital gains and other asset-related taxes, while weaker growth increases borrowing and higher unemployment adds to benefit expenditure.

Conversely, a stronger labour market would materially improve the fiscal outlook. Under the OBR's cyclical upswing scenario – in which unemployment falls to its equilibrium rate of 4.1% by 2028, two years ahead of the central forecast – higher earnings growth would lift income tax and NICs receipts, raising headroom to around £40bn total.

Mats Persson, EY UK&I Macro and Geostrategy Leader, said: “This analysis highlights how exposed the UK's fiscal position has become to events well beyond its borders. Energy market disruption originating in the Middle East has fed through into inflation, growth and borrowing costs, and UK gilt yields have reached their highest levels this century.

“The geopolitical backdrop may be outside the Government’s control, but strengthening the supply side of the economy, such as by unlocking stronger productivity or creating the conditions for sustained business investment, would build capacity to help absorb external shocks. That is a longer-term agenda than any single Budget but will ultimately determine how much room future Chancellors have to work with.”

Limited revenue-raising options available at Budget

The analysis also highlights a limited pool of significant revenue-raising measures available at the Autumn Budget. The UK Government currently raises £1.1trn in total tax receipts, with income tax, corporation tax, employee national insurance contributions (NICs) and VAT accounting for £772bn (70%) of that total. These taxes represent around 70% of the UK’s total tax take, and the Government has previously pledged not to raise the rates of the measures.

Of the taxes that make up the remaining 30% of UK tax revenues, more than half could prove politically or practically challenging to increase, including employer NICs (7% of total revenues), council tax (5%), business rates (3%) and fuel duty (2%). This would leave those measures contributing 13% of current tax receipts, including capital gains, duties and sector-specific levies.

Chris Sanger, EY UK Tax Policy Leader, said: “Manifesto commitments have ruled out rate rises in the four largest taxes, which together account for 70% of UK tax receipts. Other than extending the tax bases of those measures, the Chancellor is left with a relatively narrow and shallow pool of revenue raising options at the Autumn Budget that would individually tend to raise hundreds of millions rather than billions.

“We could see the Government’s larger ambitions signalled rather than funded at this Budget, with some of the more significant spend decisions deferred until the economic outlook is clearer or funded from post-election tax rises. This would limit the immediate impact on households and businesses, but it postpones rather than alleviates the underlying fiscal pressure.”

A limited Budget could be largely funded without manifesto-protected taxes

According to EY analysis, a limited Autumn Budget focused on pre-announced measures would require the Chancellor to find at least £12bn in additional raised revenue. This would include £9bn to repair the headroom lost since March, as well as £2.1bn to cover commitments already announced, such as the national bus fare cap, business rates relief for pubs and live music venues, and a VAT cut on household electricity bills.

EY's analysis suggests this could be met almost entirely through the introduction of smaller measures that preserve the Government's manifesto pledges. Changes to the fiscal rules could provide a particularly significant lever, with the option to reclassify around £5bn of the Government's £20bn R&D budget as capital rather than current expenditure.

However, funding a more ambitious Autumn Budget that includes some of the additional spending measures discussed in recent months could add a further £40bn of spending on top of the £12bn targeted package. Additional Government spending measures could include accelerating council house building to 50,000 homes a year (£12bn), raising defence spending to 3% of GDP (£10bn) and making social care free at the point of use (£10bn), with a further £8.4bn required to unfreeze the personal allowance from 2027 to 2030.

Unlike a more limited Budget, EY's analysis indicates this could not be funded without drawing on the manifesto-protected taxes.