Charles heads to the United States on Monday for a four-day trip, with transatlantic tensions over the Iran war and scandals linked to the late US sex offender Jeffrey Epstein threatening to intrude on the landmark visit.

Asked by the BBC whether Charles’s visit could help repair the relationship between the US and UK, Trump told the BBC: “Absolutely. He’s fantastic. He’s a fantastic man. Absolutely the answer is yes.”

Charles will be making his first state visit to the US as a monarch, at the request of the UK government and Trump. He will travel to the US with Queen Camilla and then visit Bermuda alone.

Trump has harshly criticised British Prime Minister Keir Starmer for not joining the US-Israeli war on Iran, launched on February 28.

The president commented in his phone interview with the BBC on the military response of US allies, including Britain, saying “they should have been there”, while adding: “I didn’t need them, obviously.”

Starmer has been mired in a political scandal over appointing Labour grandee Peter Mandelson, a known associate of Epstein, as UK ambassador to Washington.

Trump told the BBC that Starmer could only “recover” from the setback if the prime minister “opened the North Sea” to increase oil and gas extraction and “his immigration policies became strong”.

“But if he doesn’t, I don’t think he has a chance,” the US leader added.