UK budget faces pressure from Iran war, analysts warn

UK faces very difficult trade-offs in budget because of Iran, analysts warn

The UK government may have less room for manoeuvre in the next autumn budget than previously expected if the Iran war continues to keep oil prices elevated and inflation sticky, according to the National Institute of Economic and Social Research.

The thinktank said the situation would leave the new prime minister with a challenging inheritance and force difficult choices over spending, public services and welfare. In a business and economic context, that warning matters because higher energy prices can feed through into the wider economy, lifting costs for households, firms and the public finances at the same time.

UK faces very difficult trade-offs in budget because of Iran

NIESR said it expects inflation to rise to 3.8% over the next seven months if the current pressures persist. The organisation also said oil prices briefly moved back above $100 a barrel, underscoring how sensitive markets remain to the conflict and the situation around the Strait of Hormuz.

According to the source report, the waterway has been all but closed since March, a development that has helped push up oil prices and added to inflationary pressure. For policymakers, that combination can make budget planning more difficult because it narrows the space available to fund priorities without either raising revenues, cutting spending or accepting weaker fiscal room.

NIESR said the Treasury’s budget headroom has also been reduced in its view. It cut its forecast for the chancellor’s spending headroom from just over £7bn to nearer £3bn. That revision suggests less flexibility for ministers as they try to balance their plans for public services against higher costs in the wider economy.

The thinktank said the chancellor, John Healey, would need to find an extra £24bn by the end of the decade to maintain services and real-terms welfare payments. That estimate highlights the scale of the fiscal pressure described by the institute, particularly if inflation stays higher for longer.

The warning also sits against the backdrop of the Office for Budget Responsibility’s earlier assessment. In March, the OBR estimated that the Treasury had about £22bn of spare capacity above existing spending commitments. NIESR’s lower estimate of headroom points to a narrower margin than that earlier official figure, although the two numbers come from different institutions and reflect different assumptions.

For the government, the immediate importance of the warning lies in the choices it may face at the budget. If spending pressures rise while revenue assumptions remain under strain, ministers may have to decide how far to protect services, how much support to give households and whether to revisit existing plans.

The economic backdrop also matters because inflation affects more than the public accounts. Persistently higher prices can weigh on consumer spending, complicate business planning and make it harder for policymakers to restore confidence in forecasts. That is why energy shocks linked to geopolitical risk often end up becoming fiscal as well as market stories.

NIESR’s assessment suggests the combination of oil-market disruption and inflation could create a more constrained budget environment than the government might otherwise have faced. The next autumn budget will therefore be watched not only for headline tax and spending measures, but for how far ministers can stretch limited fiscal headroom while meeting their policy commitments.