Sir Keir Starmer left the door open to future tax hikes to fund his commitment to spend 5% of national income on defence. The Prime Minister insisted Labour would “stick to our manifesto commitments” not to raise taxes for “working people”.

But the pledge only applies to the duration of this Parliament, with another election due by 2029. Asked if tax increases would be needed to pay for higher defence spending, Sir Keir said: “Every time we’ve set out our defence spending commitments, so when we went to 2.5% in 2027/28, we set out precisely how we would pay for it, that didn’t involve tax rises.

“Clearly we’ve got commitments in our manifesto about not making tax rises on working people and we will stick to our manifesto commitments.”

The Prime Minister will promise to boost spending on defence and security to 5% of GDP (gross domestic product) by 2035 at the Nato summit in The Hague.

Sir Keir and other leaders of countries in the military alliance are expected to agree the target at the gathering in the Netherlands.

It includes spending 3.5% on “core defence” and another 1.5% on “resilience and security”.

It is a major jump from the current 2% target for Nato members, and from Labour’s aim to spend 2.5% from 2027 and 3% at some point after the next general election.

It comes amid pressure from US President Donald Trump who has demanded that Nato allies contribute more to European defence.

Ahead of his trip to the Netherlands, Sir Keir said the bumped up target was “an opportunity to deepen our commitment to Nato and drive greater investment in the nation’s wider security and resilience”.

He said: “We must navigate this era of radical uncertainty with agility, speed and a clear-eyed sense of the national interest to deliver security for working people and keep them safe.”