Keir Starmer insisted plans to increase defence spending are “cast iron” but refused to set a date for the pledge as he headed to Nato.
In his first international trip just days into the new job, the Prime Minister flew to Washington where he will meet US President Joe Biden for the first time.
Ahead of the visit, Sir Keir announced he was launching a major review of the global threats Britain faces in an increasingly dangerous world.
The Prime Minister said: “There is no more important duty for me as Prime Minister than keeping the people of our country safe.
“At a time when we face multiple threats at home and abroad, we must make sure we are ready to defend ourselves. That’s why I have immediately ordered a root-and-branch review that will secure Britain’s defences for the future.
“Working with our most important partners around the world, our Strategic Defence Review will make sure the UK is sending a clear message to those who seek to undermine
peace and democracy – you will not succeed.”
The Prime Minister’s first international trip will be closely watched for his interactions with world leaders.
Sir Keir’s decision to take his new Europe minister, Nick Thomas-Symonds, is likely to raise concerns among Brexiteers about Labour’s intentions over future relations with Brussels.
Downing Street was unable to say when or how often a minister holding the role has attended Nato before.
Brexit negotiator Lord Frost has warned Labour “can’t be trusted” with Brexit.
Sir Keir will attend a glitzy dinner in the White House hosted by President Biden and wife Jill for all of the leaders.
Wife Lady Victoria, who has so far tried to maintain a low profile, is also attending and joined her husband on the government plane out last night.
Sir Keir is expected to try and squeeze in some time to watch England play The Netherlands in the World Cup semi final today (WED).
The summit marks Nato’s 75th anniversary summit and Sir will stress his commitment to “face down” Britain’s adversaries.
A Strategic Defence Review will examine the UK’s continuing response to Vladimir Putin’s invasion of Ukraine, Middle East instability and the rise of authoritarian countries such as China and Iran.
It will put the alliance at heart of the UK’s defence plans as well as setting out how the UK will reach the target of spending 2.5% of national income on defence.
But Sir Keir has repeatedly refused to match the previous government’s commitment to hit the higher level by the end of the decade.
The PM will tell counterparts that he is determined to make sure the UK is a “leading defence player” on the world stage.
Speaking before flying to Washington DC for the Nato summit the Prime Minister was asked if he had a message for Russian tyrant Valdimir Putin.
he said: “My message is very, very clear that this Nato summit is an opportunity for allies to stand together to strengthen their resolve, particularly in light of that appalling attack against Russian aggression.
“I’m pleased to have the early opportunity to confirm and reaffirm Labour’s strong support, unshakeable support for Nato.
“We are a founding member, it’s now the 75th anniversary but this is an opportunity to send that message in relation to Russian aggression wherever. But that attack last week was appalling so that message is even more important than it was before.”
Pressed on when the new government would boost defence spending to 2.5% he said: “The most important thing is to, at this Nato summit, recommit to our solidarity with and standing with Ukraine and discuss the practical plans for further action we can take together in relation to Russian aggression.
“In relation to defence more generally, we will carry out our strategic review to look at the challenges, the capabilities, and on the back of that make further plans.
“I am committed to that 2.5% within our fiscal rules.
“That strategic review needs to come first. But today, tomorrow and the next day is all about standing together with our allies, discussing practically how we provide further support to Ukraine, and send a very, very clear message to Putin that we will stand against Russian aggression wherever it is in the world.”
Defence Secretary John Healey said: “Britain’s commitment to Nato is unshakeable. We cannot have prosperity without security and we must never take our ability to live freely for granted.”
The trip will be the PM’s first official visit on the world stage having won a landslide majority with fellow leaders including US President Joe Biden and France’s Emmanuel Macron enduring domestic woes.
A Number 10 spokesman said: “Now more than ever he thinks it’s important that we come together with our like minded partners across the world in a show of strength and collaboration.
“Because everything he will try to achieve in government from now on depends on the security of our nation.
“Without national security, we cannot achieve stability and prosperity for the British people and deliver on the missions the Prime Minister has set out.”
The US leader has been under intense scrutiny following a dire performance during a CNN television debate against Donald Trump.
Sir Keir is facing pressure in the UK from ex-head of the army General Sir Patrick Sanders to go beyond 2.5% to closer to 3%.
