Delays in publishing the Government’s long-awaited Defence Investment Plan have undermined Britain’s credibility with allies and could leave the Armed Forces paying more for vital equipment, MPs have warned.
A report from Parliament’s Public Accounts Committee (PAC) criticised the continued absence of the Defence Investment Plan (DIP), which was originally expected last autumn but is now due to be published ahead of the upcoming NATO summit.
The plan is intended to outline how defence equipment, infrastructure and military capabilities will be funded over the next decade, following the publication of the Strategic Defence Review earlier this month.
Sir Geoffrey Clifton-Brown MP, chairman of the Public Accounts Committee, said Britain had effectively gone years without a credible long-term military capability plan.
He argued that explanations about taking extra time to finalise the details were no longer sufficient and suggested ministers should acknowledge the delay rather than continue defending it. He also warned that the absence of the plan sends an unhelpful message to Britain’s allies, the public and potential adversaries.
The committee found that uncertainty over future procurement has coincided with rising costs across the global defence industry. With defence manufacturers facing increasing demand and international instability driving up prices, MPs warned that further delays could ultimately leave taxpayers facing a larger bill.
The report also argued that the lack of a clear investment strategy risks slowing efforts to modernise Britain’s military and prepare the Armed Forces for future conflicts. According to the committee, delays in deciding which capabilities, infrastructure projects and personnel investments are required have contributed to the hold-up.
The Ministry of Defence defended its record, stating that it is working to finalise the plan and describing it as part of a wider effort to address what it called an “outdated, overcommitted and underfunded programme” inherited from previous administrations. Officials also noted that more than 1,400 major defence contracts have been signed since July 2024 and pointed to increased defence spending commitments.
The PAC report also highlighted ongoing concerns surrounding the troubled Ajax armoured vehicle programme.
Army use of the vehicles was paused in late 2025 after soldiers reported health problems linked to noise and vibration. The committee found that 33 personnel had been affected, with five still under medical review as recently as March this year. MPs questioned whether current operating restrictions are practical in combat situations, particularly as crews are required to carry out maintenance checks whenever the vehicles stop.
The committee further expressed concern over the Ministry of Defence’s management of major financial programmes, including Britain’s nuclear deterrent.
According to the report, around 18 per cent of the defence budget, approximately £10.9 billion, is currently spent on the UK’s nuclear programme. That proportion could rise to as much as 25 per cent in coming years as work continues on the new Dreadnought-class submarines, which are expected to carry the nation’s Trident nuclear missiles.
MPs called for greater transparency over nuclear spending and urged the Ministry of Defence to provide Parliament with more detailed information on costs and performance. They also raised concerns about accounting discrepancies involving more than £6 billion in defence assets.
Among its recommendations, the Public Accounts Committee has called on the Ministry of Defence to explain how it will minimise the impact of delays on defence suppliers, provide a timetable for making the Ajax vehicle fit for service, improve military recruitment efforts and offer greater transparency over the UK’s nuclear programme.
The report comes amid wider questions about Britain’s military readiness. The Ministry of Defence recently responded to reports that all five of the Royal Navy’s Astute-class attack submarines are currently awaiting repair work. Officials insisted that protecting British waters remains a top priority and said a range of naval and air assets continue to safeguard the nation’s security.
With NATO allies increasing defence spending and the war in Ukraine continuing to reshape security priorities across Europe, pressure is mounting on ministers to publish the Defence Investment Plan and provide greater clarity over the future direction of Britain’s armed forces.
