The former Labour prime minister, Blair, said Keir Starmer “should have backed America from the very beginning” and let the Trump administration use British airbases, adding: “If they are your ally and they are an indispensable cornerstone for your security … you had better show up when they want you to.”

Axar.az reports, citing The Guardian, that Blair’s intervention comes as Trump intensifies his criticism of Starmer over the lack of immediate UK support for the US-Israeli strikes on Iran, saying on social media: “We don’t need people that join Wars after we’ve already won!”

Blair has been fiercely criticised over the past two decades for his decision to join the US invasion of Iraq in 2003.

At a private Jewish News event on Friday, he stated that he had already made his criticism clear to the government. He told those at the event that alliances were tested “when it’s hard”, saying the bases were needed for refuelling and adding that the conflict was “not like Vietnam”.

“It’s not like the Iraq campaign [where] we sent thousands of British troops. So I just think you’ve got to make the argument to the public about this.”

He said. “You’ve got to say to them the American relationship matters. It matters particularly today. It’s not a question of whether it’s this president or that president.”