Sir Keir Starmer is about to make his last appearance on the global stage as Prime Minister in what may be a legacy-defining moment – unless Donald Trump ruins it for him.

Starmer arrives at this week’s Nato summit in Turkey after a last-minute defence spending announcement he hopes will satisfy allies and salvage the UK’s reputation as a leading military nation.

But he will fear being berated by the US President at the summit in Ankara, who has been critical of the UK’s policy on Iran and has often chided him for not doing enough.

Will the Prime Minister’s £15bn spending plan please the US President? Starmer said it would bring defence spending to 4.2 per cent of UK GDP if energy security and critical infrastructure is included, closer to the 5 per cent pledged at last year’s Nato summit.

But a close look at the numbers, if Trump looks that closely, signals trouble.