The president of the United States, Joe Biden, has called Liz Truss's original economic policies "a mistake."

In an unusual intervention, he said the economic turmoil that followed the government's mini-budget had been "predictable."

Speaking at an ice cream shop in Oregon, Mr Biden was asked by reporters about the prime minister's attempt to boost growth with unfunded tax cuts - what the reporter called the "trickle-down plan that she has had to back away from."

The president replied: "Well, it's predictable. I wasn't the only one that thought it was a mistake."

He added: "I think that the idea of cutting taxes on the super wealthy at a time when - anyway, I just think - I disagreed with the policy, but that's up to Great Britain to make that judgment, not me."

Mr Biden has long been critical of the economic theory at the heart of the prime minister's policy, namely that cutting taxes on businesses and the rich generates growth that allows wealth to "trickle down" to all sectors of society.

But it is unusual for the president of the United States to be so critical of the leader of one of America's closest allies.

Mr Biden has been criticised in the past for not doing enough to support UK-US relations, preferring instead to focus his transatlantic relationship on Dublin, Paris and Berlin.

But he is not alone on the world stage in being puzzled at the way Britain is being governed and the choices being made by its politicians.

Greek Prime Minister Kyriakos Mitsotakis has also joked about the UK's economic upheaval

Foreign ministers and British diplomats say there is a diplomatic cost to Britain's political turmoil, as well as an economic price.

Some world leaders are even happy to laugh at Britain's expense in public. The Greek Prime Minister Kyriakos Mitsotakis spoke to the Sunday Times about the concerns expressed by the International Monetary Fund about the state of Britain's economy.

"If you need experience in dealing with the IMF, we are here to help!" he joked, a reference to Greece's own financial instability and support from the international body.

Diplomats from countries suffering their own economic turmoil joke that their currency is stronger than the pound.

And crucially, foreign diplomats feel able to break one of the first rules of diplomacy and criticise the domestic policies of their host governments, such as the German ambassador in London, Miguel Berger, who voiced his concerns about the government's economic plans.

Liz Truss insists she will see through her "mission" to get Britain's economy growing

One UK diplomat told me: "We are a laughing-stock. People come up to me and ask: 'What is going on in your country?' There is a grim fascination in it all. But when I want to talk about substance, they just say, "let's wait until things have settled down and there's a plan.'"

Foreign diplomats and ministers say they miss the role the UK used to play on the world stage, saying they long to see what some describe as "the Britain of old," that provided a calm, steady presence on the world stage.

Britain was in the past seen by diplomats as one of those countries that followed due process and the rule of law and tended to be on the sensible side of any argument.

One European foreign minister told me this weekend: "Wake up Britain! The world is on fire. We need you."

The international unease has been noted by the main opposition parties in the UK, with shadow foreign secretary, David Lammy, saying the recent turmoil has "made Britain's economy an international punchline".

"President Biden knows the dangerous folly of trickle-down economics," the MP continued. "His comments confirm the hit our reputation has taken thanks to the Conservatives."

The BBC approached the Foreign, Commonwealth and Development Office for a response, but it said it would not be commenting. (BBC)

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