Britain will be forced to sign up to a target to hike defence spending to 3.5% of GDP by 2035 at a Nato summit later this month in a bid to appease Donald Trump, defence sources believe.
On Monday Keir Starmer’s bold plans to transform the UK’s defences were overshadowed by a row over money after the prime minister failed to commit to a firm date to raise spending to 3% of GDP.
The Labour leader was warned Britain may not be moving quickly enough to counter the rapidly growing threats from countries such as Russia.
Sir Keir and other Nato leaders are also under pressure from US president Donald Trump to rapidly increase spending, to wean Europe off a dependence on Washington for military support.
Now amid attempts by Nato’s secretary general Mark Rutte to woo President Trump, senior defence sources say said Britain will “without a doubt” sign up to a proposal for member countries to boost defence spending.

It would involve countries agreeing to spend 3.5% on hard defence with another 1.5% on areas such as cyber, intelligence and military-related infrastructure, at a summit in the Hague in a few weeks.
One senior insider said Britain would “without a doubt” sign up, The Guardian reported.
Last week Mr Rutte said: “I assume that in The Hague we will agree on a high defence spend target of in total 5%.” He added that it would be “considerably north” of “3% when it comes to the hard spending”.
On Tuesday the defence secretary failed to rule out tax rises to make Britain “war ready”, amid concerns that the government does not have enough money to fund the plans outlined in the defence review.
John Healey said the government would “set out how we’ll pay for future increases in the future” when quizzed over how Britain can afford to boost its military funding to 3 per cent.
A day after Sir Keir Starmer unveiled the long-awaited defence strategic defence review, Mr Healey said he is “100 per cent confident” the target would be met — but he struggled to say how it would be paid for after economists warned that significant tax rises would be needed.
The PM’s official spokesman said the UK’s “commitment to Nato is unshakeable, we’ve always put Nato at the heart of our approach to defence.”
He added: “As the prime minister said yesterday, there will always be discussions about the contribution going into Nato in the lead up to the conference.”
The UK is already the third highest spender in Nato in cash terms, behind just the US and Germany.