Is the UK about to unleash one of the biggest defence spending boosts in decades?
Behind closed doors in Downing Street, discussions are intensifying over whether Britain should ramp up military investment far sooner than planned, at a potential cost of billions of pounds.
Reports have learned that the Prime Minister, Keir Starmer, is considering bringing forward an existing commitment to raise defence spending to 3% of GDP, a target originally framed as an “ambition” for the next Parliament.
Now, aides are examining whether that goal could be met before the end of the current Parliament, which could run until 2029.
No decision has been taken. And the Treasury, we’re told, is cautious.
“Spend More, Faster”
Sir Keir made his tone unmistakably clear at the Munich Security Conference over the weekend.
“To meet the wider threat, it’s clear that we are going to have to spend more, faster,” he told world leaders, arguing that Britain must strengthen its “hard power” in response to growing global instability, particularly the threat from Russia.
He has already pledged to raise defence spending to 2.5% of GDP by April 2027. But the bigger headline promise was an ambition to hit 3% in the next Parliament.
Now, that timeline could be dramatically accelerated.
The Bill Could Be Eye-Watering
Bringing the 3% target forward by as much as five years would not come cheap.
The Office for Budget Responsibility calculated last year that reaching 3% of GDP on defence would cost an additional £17.3bn per year by 2029–30.
Meanwhile, the Institute for Fiscal Studies estimates the true additional cost, taking existing increases into account, could be closer to £13–14bn annually.
For context, the UK spent around 2.3% of GDP on defence last year, roughly £66bn.
And there’s an even bigger commitment looming: alongside other Nato allies, Britain has signed up to spend 3.5% of GDP on core defence by 2035.
In other words, the direction of travel is clear. The only question is how quickly, and how painfully, the country gets there.
A Budget Already Under Strain
The backdrop to all this is a defence budget that insiders say is already stretched thin.
Reports last month suggested the Ministry of Defence requires an extra £28bn over the next four years just to meet existing commitments.
In January, Chief of the Defence Staff Richard Knighton told MPs bluntly:
“We cannot do everything we would want to do, as quickly as we want to do it, within the context of the budget we have set.”
Officials say that sobering realisation, that previous spending plans will not cover rising costs and existing bills, is driving the push to accelerate the 3% target.
One defence source described Sir Keir’s Munich speech as “an argument for increased defence spending with the announcement left out”.
Treasury Tensions and Political Fallout
The proposal was discussed at a key strategy meeting earlier this month as part of the long-delayed defence investment plan. But tensions remain.
Whitehall insiders suggest that Morgan McSweeney, the Prime Minister’s former chief of staff, had been a strong advocate for increased defence spending. Since his resignation last weekend, some officials say the dynamic has shifted, with Treasury concerns hardening.
Treasury sources, however, reject the idea that they are blocking a specific 3% plan. They insist discussions about future defence funding are ongoing across government and led by the Prime Minister.
Behind the scenes, the question is unavoidable: where would the money come from?
Possible options floated in Whitehall include cutting Overseas Development Assistance, scaling back net-zero projects aimed at reaching 2050 targets, or revisiting major infrastructure commitments such as the high-speed rail line between London and Birmingham.
Borrowing is another possibility, but breaching fiscal targets could risk unsettling financial markets. One source even claimed a special group has been set up within the MOD to explore ways around the government’s fiscal rules.
The MOD officially says it does not comment on speculation, stressing instead that it is already delivering the largest sustained increase in defence spending since the Cold War, including an extra £5bn this financial year alone.
International Pressure Mounts
Accelerating the 3% target would be warmly welcomed in Washington, where the United States has reportedly been urging the UK to move faster.
Sir Keir himself framed greater spending as a way to reduce reliance on America. Britain, he argued, must move “from over-dependence to interdependence”, strengthening partnerships with European allies and bolstering support for Ukraine.
Foreign Secretary Yvette Cooper echoed that message, calling the government’s pledge the biggest increase in defence investment since the Cold War, but conceding that more would be needed.
“We are going to need to go further,” she said. “Of course we will need to go further.”
The Big Question
For now, nothing is signed off.
But if the Prime Minister does decide to bring forward the 3% target, it would mark one of the most significant strategic and financial shifts in modern British defence policy.
The real debate is no longer whether Britain will spend more on defence.
It’s how much, how soon, and who ultimately pays the price.
