Britain is facing a crisis in defense funding that risks eroding its ability to defend itself and fulfill its NATO commitments. Outgoing Prime Minister Keir Starmer's long-delayed Defense Investment Plan (DIP) was released last month, with a pledge of an additional £15bn ($20bn) in defense spending over four years. Yet it left a £4.7bn ($6.3bn) funding gap in the next budget, which his presumed successor, Andy Burnham, needs to fill.
It has now emerged that an additional £10.3bn ($13.7bn) in funding is also missing. The DIP stated only that it would be financed through departmental savings, without explaining how those savings would be achieved. That means Burnham now faces the prospect of finding billions of pounds' worth of spending cuts. He will be aware that Starmer first lost his authority as prime minister when his attempt to curb the growth in welfare spending collapsed. There has been little indication since then that the governing Labour Party has developed any greater appetite for cuts.
That matters because the armed forces face a funding shortfall that even the full DIP is unlikely to address. During more than a decade of war in Iraq and Afghanistan, funding was diverted from long-term investment to meet operational requirements. Now that those wars are over, years of underinvestment have left important capabilities weakened. In addition, the war in Ukraine has demonstrated how rapidly warfare is changing. Britain therefore finds itself needing to adapt to modern warfare, make up for years of underinvestment and do so without making significant cuts elsewhere.
Warnings of a More Dangerous Europe
Since the war in Ukraine began in 2022, many serving and retired senior British military officers have warned publicly that the UK faces a growing risk of a major conflict for which its armed forces are not adequately prepared.
The Chief of the General Staff, General Roly Walker, said it was imperative that the British Army be ready for war by 2027. The Chief of the Defense Staff, Admiral Tony Radakin, has similarly warned that the international security environment is “more dangerous than [he has] known during [his] career”. NATO Secretary General Mark Rutte has also urged alliance members to prepare for the possibility of Russian aggression within the next five years.
These warnings come against the backdrop of Russia's war in Ukraine, where Moscow has suffered hundreds of thousands of casualties but continues offensive operations while expanding its military mobilization and broader hybrid warfare campaign.
Britain has been among Ukraine's strongest supporters, providing military equipment, training and financial assistance. That support has also made the UK one of Russia's principal adversaries and a frequent target of hostile rhetoric in Russian state media. During the 2000s, London became a hub for wealthy Russians, but it also offered refuge to many opponents of the Kremlin. The Russian state's campaign against dissidents, including the attempted assassination of Sergei and Yulia Skripal with the Novichok nerve agent in Salisbury in 2018, contributed to a sharp deterioration in relations between London and Moscow.
While this intelligence confrontation intensified at home, British forces remained focused on counter-insurgency operations overseas. Investment therefore concentrated on capabilities such as anti-IED technology and mine-resistant vehicles rather than conventional war-fighting equipment. Russia's full-scale invasion of Ukraine fundamentally changed those assumptions, forcing the British armed forces to refocus on high-intensity warfare in Europe.
An Army Shrunk by Years of Underinvestment
Not only did overseas wars shift the priorities of military spending, but their end was also seen as an opportunity to reduce defense costs. The British Army has fallen to fewer than 75,000 regular soldiers, its smallest size since before the Napoleonic Wars. Even at that reduced strength, it struggles to recruit enough personnel. The recruitment crisis has been driven by a combination of failures by the outsourced company responsible for recruitment, the absence of active conflicts attracting those seeking combat roles and growing political disillusionment among groups that have traditionally supplied recruits.
In addition, the emphasis on equipment for counter-insurgency operations has come at the expense of conventional warfighting capabilities. Although the Army officially has more than 200 Challenger 2 tanks, many are unavailable because of maintenance issues. The current program to upgrade part of the fleet to the Challenger 3 standard will reduce the number of operational tanks to fewer than 150.
These problems have been compounded by repeated procurement failures within the Ministry of Defense, most notably the Ajax armored fighting vehicle program. Intended to provide a family of interoperable armored vehicles that would underpin the Army's future reconnaissance capability, the project has suffered years of delays, billions of pounds in cost overruns and serious technical defects. During testing, excessive vibration and noise levels caused injuries to some soldiers, forcing repeated redesigns and delaying the program.
As a result, one official assessment concluded that if the Army were deployed in a conflict as intense as the war in Ukraine, it could be “expended" within as little as six months.
Britain's ultimate guarantee of national security is its nuclear deterrent, which is carried aboard ballistic missile submarines that maintain a continuous at-sea deterrent. However, that capability has also faced growing criticism. Former Downing Street adviser Dominic Cummings has repeatedly argued that Britain's nuclear deterrent is not operating as intended and that the program's costs have spiraled beyond control.
The Political Challenge of Paying for Rearmament
The DIP was intended to address many of these shortcomings by setting out a comprehensive investment plan to rebuild the British armed forces. Although there is broad political agreement on the need to rearm, Britain's weak economic growth means that higher defense spending can only be achieved by cutting expenditure elsewhere.
The plan called on every government department to find 1% in savings, which would release the £15bn ($20bn) required for the DIP. Some of the largest departments, including the Department for Transport and the Department for Energy Security and Net Zero, were expected to make larger reductions because of their sizeable budgets.
Beyond a handful of relatively small road projects, however, few such savings have been identified. There has been speculation that hospital construction budgets could come under pressure, although ministers have insisted that repairs to hospitals affected by reinforced autoclaved aerated concrete (RAAC) and previously announced hospital projects will not be affected. The government also says it intends to protect frontline public services.
In doing so, however, it risks repeating the mistake that helped create the current defense funding gap. Reducing investment in core military capabilities allowed Britain to sustain overseas operations without significantly increasing defence spending. Over time, however, years of underinvestment created larger financial pressures. Delaying investment in roads or hospitals may reduce spending in the short term, but it could also result in higher costs in the future.
There are areas where savings could potentially be made. Spending on the asylum system has risen sharply in recent years, reaching billions of pounds, while more than 200,000 migrants have arrived illegally in small boats across the English Channel since 2020. Addressing those costs would likely require changes to Britain's human rights framework, a politically difficult step for many Labour politicians.
Similarly, benefit spending has increased substantially since the Covid-19 pandemic.
Starmer’s attempt to slow the growth in welfare spending ended in a parliamentary defeat from which his government never fully recovered. Efforts to balance the public finances through other measures, including higher taxes on farmers, also proved politically unpopular.
Burnham may therefore find himself facing an increasingly difficult political choice. Defense spending is widely expected to rise further, with the DIP projected to increase military spending to 2.69% of GDP by 2030, still well below NATO's new 3.5% benchmark. Funding that increase would require either cuts to infrastructure spending, potentially creating higher costs in the future, or politically contentious reductions in welfare spending. Neither option is likely to be easy.
Even if the immediate risk of military conflict proves lower than some defense planners anticipate, years of underinvestment have left Britain's conventional armed forces and nuclear deterrent under growing strain. Delaying difficult decisions further could weaken the country's long-term security.
