UK government defence plan leaves £4.7 billion funding gap for next budget

The UK government published a Defence Investment Plan on Tuesday that adds £15 billion to military spending over four years while confirming only £10.3 billion of that total. The remaining £4.7 billion will be settled at the 2026 Budget, the Treasury stated in a written parliamentary statement.

The plan also cancels or postpones projects in energy, infrastructure and military housing to help meet the £10.3 billion already identified. It increases defence spending by £1.5 billion more than the amount secured by the previous defence secretary before his resignation.

Funding timeline and process A defence minister told Sky News that the incoming prime minister received a briefing on the plan but learned of the £4.7 billion gap only when Treasury figures were released on Tuesday. The same minister declined to say exactly when that conversation occurred.

The defence secretary rejected claims that the gap was created as a deliberate problem for the next government. He said conversations with the incoming prime minister would continue and that he would continue to press for defence funding.

Budget implications The Treasury said the outstanding amount would be confirmed "in a fair and balanced way" at the 2026 Budget. Transport and energy departments face steeper cuts than other areas, though specific projects have not been named. An economist at the Institute for Fiscal Studies said the shortfall would require further decisions on spending, tax or borrowing beyond those already announced.