Keir Starmer is facing pressure to find more money for UK forces amid warnings of a £28billion funding black hole.
The PM is said to have been warned by the chief of the defence staff that there is a huge gap in budgets over the next four years.
The shortfall raises the prospect of the military needing to make deep cuts – as fears over a direct confrontation with Russian mount.
Sir Keir has also been trying to defuse tensions with Donald Trump over Greenland by pledging to do more to protect the strategically-crucial Arctic.
There were already questions over whether Britain was spending enough as the US focuses on the Pacific and threats intensify.
The government has pledged to boost defence spending to 2.5 per cent of GDP by 2027, and set out an ambition of reading 3 per cent in the next Parliament ‘when fiscal and economic conditions allow’.
Keir Starmer is facing pressure to find more money for UK forces amid warnings of a £28billion funding black hole
The PM is said to have been warned by the chief of the defence staff Richard Knighton (pictured) that there is a huge gap in budgets over the next four years
However, senior military figures have warned that significantly more investment is needed.
Forces head Air Chief Marshal Sir Richard Knighton delivered the grim news to Sir Keir in Downing Street before Christmas, according to reports.
Chancellor Rachel Reeves and Defence Secretary John Healey were also at the meeting to be informed about the £28billion shortfall by 2030.
Sir Keir was said to be deeply unhappy because the strategic defence review (SDR) was meant to have been ‘fully costed’.
The defence investment plan to deliver the SDR could now be delayed until March while officials work out what to do about the issue.
Factors being blamed include higher inflation, pay rises for troops and the cost of the nuclear deterrent.
A military source told The Times that cuts were inevitable, despite anxiety that the army is already at an historically small size.
Sir Keir has committed to putting troops on the ground in Ukraine if there is a peace deal, but experts have voiced doubts about whether even a 7,500 deployment would be feasible currently.
‘You need to seek some big-ticket items. They [ministers] have to make big decisions about big things,’ one senior source said.
Chancellor Rachel Reeves and Defence Secretary John Healey were also at the meeting to be informed about the £28billion shortfall by 2030
An MoD spokesman said: ‘The UK defence budget is rising to record levels as this Government delivers the biggest boost to defence spending since the Cold War, totalling £270billion this parliament alone.
‘Demands on defence are rising, with growing Russian aggression, increasing operational requirements and preparations for a Ukraine deployment.
‘We are working flat out on the Defence Investment Plan, which will fix the outdated, overcommitted, and underfunded defence programme we inherited.’
