Britain has endured more than a decade of under-investment in defence, having increased its defence budget by just 14% in that time in to 2022 cash terms, according to research from the House of Commons library.
Russia has increased defence spending by 34% – taking its total to $109bn in 2025, which is 5.9% of its GDP – Iran by 57% and China 60% over the last 10 years.
The biggest increase in defence spending was seen between 2021 and 2022, when the Ukraine war started.
The new Labour government is subsequently facing calls to fulfil its promise to increase defence spending from its current level of 2.3% of GDP.
The ministers pledged to take it up to 2.5% of GDP in its October Budget, but did not say when they would meet that commitment.
Instead the government have set out a defence spending review which they say will be published in the spring.
So the Liberal Democrats have warned PM Keir Starmer that Russia, Iran and China have boosted their defence expenditure by an average (50%) which is more than three times more than the UK has (14%).
Helen Maguire, Lib Dem spokesperson for defence, said: “With war waging on our continent, hostile states increasing their defence spending and an unreliable partner elected across the Atlantic, it is vitally important for Britain’s defences to be strengthened.
“The previous Conservative government neglected our armed forces and left our Army at its smallest size since the era of Napoleon.”
The party called for the government to set out its plans to increase defence spending before Donald Trump takes to the White House in January.
The president-elect will be pushing for all Nato members to increase their defence spending commitments – some reports say he could pressure them to increase it by up to 5% of their GDP, up from the current 2% mandatory commitment.
The UK’s defence spending has dropped off since the Cold War ended, but Maguire said: “It’s time for the UK to lead in Europe when it comes to the defence of our continent.”