The UK's Defence Investment Plan (DIP) was meant to be a flagship achievement for Sir Keir Starmer's premiership — a long-promised blueprint to prepare the country's armed forces for future conflicts. Instead, its unveiling on 1 July 2026 sparked a political row over a missing £4.7bn, with the prime minister's successor, widely expected to be Andy Burnham, left to find the money.
The DIP commits an extra £15bn to defence by 2030, funding weapons such as nuclear missiles and drones. But the Treasury has only identified £10.3bn in savings to pay for it. The remaining £4.7bn — roughly £1bn a year over four years — is not yet allocated. Chancellor Rachel Reeves has said this is normal, as the sum will be found in the next Budget. However, critics, including Conservative leader Kemi Badenoch, argue the plan is unfunded and amounts to a "black hole" left for the next prime minister.
“Explains the UK's Defence Investment Plan and the £4.7bn funding gap highlighted by political leaders.”
The row over the DIP is the latest chapter in a long-running debate about how to balance defence spending with other demands on the public purse. The UK's defence budget has faced pressure for years: the previous Conservative government cut spending, according to Sir Keir, and military chiefs have repeatedly called for more investment. The DIP itself falls short of the £28bn reportedly demanded by former defence ministers John Healey and Al Carns, who resigned in protest. Meanwhile, the wider economic picture is tough — an anaemic economy, high tax burden, rising national debt, and a spiralling benefits bill.
For UK readers, the implications are direct. The DIP's funding gap means that the next prime minister and chancellor will face difficult choices. They could borrow more, but economists warn that the Iran war has already eaten into the government's fiscal headroom — the £22bn of spare borrowing capacity calculated by the Office for Budget Responsibility. Ruth Curtice of the Resolution Foundation said the DIP would reduce that headroom by about £2bn, on top of other pressures. Alternatively, the government could cut other departments' capital budgets — sources say £2bn of reductions are being considered at the energy department — or raise taxes. The key point is that every option involves trade-offs that affect public services, taxes, or both.
The plan also provokes broader questions about how the UK funds its defence in a changing world. Sir Keir acknowledged that "there will always be those who say, whatever the sum is frankly, it is not enough." But the immediate challenge for Mr Burnham will be finding that £4.7bn without derailing other commitments.
Q: Why is the Defence Investment Plan £4.7bn short? The plan totals £15bn of extra spending, but the Treasury has only allocated £10.3bn in savings from other budgets. The remaining £4.7bn is expected to be found in the next Budget, which will be set by the new chancellor. Critics say this leaves an unfunded commitment for the next government.
Q: Who is Andy Burnham and why is he involved? Andy Burnham is the MP for Makerfield and is widely expected to become prime minister on 20 July 2026, succeeding Sir Keir Starmer. As the likely next PM, he will inherit the task of funding the DIP's gap. Sir Keir has suggested Burnham use the fiscal headroom built into the Budget.
Q: What happens if the money isn't found? If the £4.7bn is not allocated, the DIP would be underfunded. This could delay or reduce planned investments in drones, nuclear missiles, and other capabilities. Defence chiefs and former ministers have already said the plan is inadequate without the full funding.
What happens next depends on the transition of power. Sir Keir will attend the Nato summit in Ankara next week — his last scheduled foreign event as prime minister. Then, on 20 July, Andy Burnham is expected to take over. He will have to decide how to fund the DIP, either by borrowing, cutting other spending, or raising revenue. The autumn Budget will be the key fiscal event where the details must be set out. For now, the political battle lines are clear: Sir Keir says he has left the country in a better state; his opponents say he has left a mess.