The United Kingdom’s fiscal headroom has shrunk by approximately £12 billion since the spring, increasing pressure on Chancellor John Healey to consider tax rises or spending cuts in his upcoming budget. According to recent economic analysis from professional services firm KPMG, the government’s room for maneuver to meet its fiscal rules now stands at £11.6 billion—less than half the £23.6 billion reported earlier this year.

This decline follows a combination of slower economic growth and higher public borrowing costs, which have risen to their highest levels in 19 years amid ongoing global uncertainties, including the conflict in Iran. Inflation has also resurged, with forecasts suggesting it will rise to around 4% early next year, reversing some recent easing and prompting expectations of further interest rate hikes. Meanwhile, market interest rate predictions have increased by around one percentage point since spring, further raising the government’s borrowing costs and tightening fiscal space.

Deutsche Bank estimates that these higher borrowing costs alone will increase long-term government expenses by £13 billion. However, their analysis also indicates that rising inflation could add £2 billion in fiscal headroom, yielding a narrower net margin of roughly £8.5 billion. Additionally, the Institute for Fiscal Studies has warned that if the Office for Budget Responsibility (OBR) revises down population growth projections, particularly due to reduced migration, government borrowing could increase by an additional £1 billion to £5 billion by 2031-32.

The chancellor has indicated that his forthcoming budget, scheduled for October 28, will aim to establish a “robust fiscal buffer against uncertainty.” This goal aligns with the government’s long-term target of balancing day-to-day public spending with tax revenues by the start of the next decade. The previous forecast of £23.6 billion in headroom, made by former Chancellor Rachel Reeves for 2029-30, was the largest since Rishi Sunak held the office in 2022.

KPMG’s Chief UK Economist, Yael Selfin, noted that restoring the previous fiscal buffer may necessitate difficult decisions on tax and spending. The government has ruled out increasing taxes on working individuals, which may lead to consideration of other tax changes, such as adjustments to capital gains or inheritance taxes. Andy Burnham, a prominent political figure, has proposed aligning capital gains tax rates with income tax to generate additional revenue; modeling from the National Institute of Economic and Social Research estimates such a move could raise around £14 billion.

Despite the fiscal pressures, recent economic data offers some positive signs. Growth in the UK economy has outperformed expectations in the first half of the year, with KPMG forecasting GDP growth of 1.3% in 2026 and a slight acceleration to 1.4% in 2027. July saw a 0.4% monthly increase in output, marking a promising start to the third quarter. Nevertheless, the Bank of England has signaled that it is poised to raise interest rates further to counter rising inflation, with market traders anticipating up to four increases in the next twelve months.

The OBR is set to finalize its fiscal outlook in the weeks ahead, incorporating updated assumptions on interest rates, borrowing costs, oil and gas prices, and demographic changes. The forthcoming budget will reflect these assessments as the government seeks to balance economic growth objectives with fiscal sustainability in a challenging international environment.