Keir Starmer says defence spending commitment ‘cast iron’ – but refuses to give timeline

“At a time when we face multiple threats at home and abroad, we must make sure we are ready to defend ourselves,” Sir Keir said.

“That’s why I have immediately ordered a root-and-branch review that will secure Britain’s defences for the future.”

Speaking ahead of his departure to Washington, Sir Keir told reporters he was committed to spending 2.5% of GDP – a measure of the size of the economy – on defence “within our fiscal rules”.

But he added: “That strategic review needs to come first.”

This suggests it will not happen quickly.

During the election campaign, the Conservatives pledged to reach 2.5% by 2030 and criticised Labour for not matching their commitment.

Labour has insisted it will hit the target when the nation’s finances allow.

Nato members have pledged to spend at least 2% of their GDP on defence by 2024 – but many are falling short of the target.

Some 23 of the alliance’s 32 member countries are projected to meet the target this year.

The UK currently spends just over 2% of its GDP on defence.

The PM is joined on this trip by Foreign Secretary David Lammy, Defence Secretary John Healey and the Paymaster General Nick Thomas-Symonds, who has a responsibility for the UK’s relations with its European neighbours.

Labour is very conscious the party is often not trusted on defence and national security – and so the language chosen by these new senior ministers is striking in its conviction, to try to underline that the party has changed from the era of Jeremy Corbyn’s leadership.

Mr Healey said “Britain’s commitment to Nato is unshakeable”, while Mr Lammy said “Nato is part of Britain’s DNA”.

This trip will also provide the prime minister with a first chance to meet fellow world leaders in his new role.

It will be the first time he has ever met President Biden.

He has met other leaders of Nato member states before, such as President Emmanuel Macron of France and Chancellor Olaf Scholz of Germany.