Barclays has concluded that the UK will have to find about 3.7 billion in additional financing in the 2026 budget to meet higher defence spending commitments, despite recent reallocations intended to partially offset the cost.
In a research note, the bank said that an announced increase of 5 billion in defence spending spread over the next four fiscal years will be only partly covered by cuts to capital budgets across departments. Those capital budget reductions amount to roughly 11.3 billion, leaving an uncovered balance of around 4.7 billion that will need to be addressed through policy changes at the time of the 2026 budget.
The analysis notes that the additional defence spending was set out by outgoing Prime Minister Keir Starmer and Chancellor Rachel Reeves. Barclays flagged the shortfall as a material fiscal challenge for the incoming government, stressing that the remaining funding must be identified in the forthcoming budget process.
Political constraints could limit the menu of options available to close the gap. Barclays highlighted comments from Andy Burnham, who is widely regarded as the frontrunner to succeed Starmer, and who has emphasised devolving powers to regional governments and avoiding major tax increases on businesses. The bank said advisers close to Burnham have pushed back against calls from some trade unions to raise taxes on banks and businesses to fund new policies, underscoring the limited appetite for large business tax hikes.
Barclays also assessed how market moves since official forecasts have affected fiscal space. The bank estimated that higher gilt yields since the Office for Budget Responsibilitys March forecasts have already trimmed available headroom by roughly 3 billion. It added that revised population projections could further reduce that margin, while estimating current budget headroom at about 15 billion to 20 billion under present market conditions.
The bank weighed the economic implications of redirecting capital spending toward defence. In the near term, Barclays argued that shifting investment from areas such as transport, energy, housing and education into defence may not have large effects on growth because the near-term fiscal multipliers of the two spending types are similar. Over a longer horizon, however, it noted that infrastructure investment typically delivers stronger productivity gains than defence expenditure.
On monetary policy, Barclays said recent remarks from Bank of England Governor Andrew Bailey align with its expectation that policymakers will hold interest rates steady this year despite easing inflation. Bailey reiterated a view that inflation is likely to peak at about 3.2% later in the year and indicated that rate cuts remain "off the table" for now. He also signalled the Bank will continue active gilt sales as part of its quantitative tightening programme.
Taken together, Barclayss assessment sketches a fiscal picture in which planned reallocations reduce, but do not eliminate, the need for further measures to fund the defence uplift. The banks numbers suggest the incoming administration will face trade-offs between political commitments on taxation and regional policy, market-driven changes to fiscal headroom, and choices over the composition of capital investment.
Summary
Barclays calculates a roughly 4.7 billion shortfall that will need resolving in the 2026 budget to fully fund an announced 5 billion rise in defence spending over four years. Cuts to departmental capital budgets cover about 11.3 billion of the pledge. Political resistance to large business tax increases and higher gilt yields have reduced fiscal flexibility, while the bank notes that diverting investment toward defence may leave longer-term productivity gains lower than alternative infrastructure investment.