US President Joe Biden has said that Liz Truss’s original economic plan was a “mistake”.

In a highly unusual intervention, the President broke diplomatic protocol by commenting on the Prime Minister’s policy saying: “I wasn’t the only one that thought it was a mistake.”

During a visit to an ice cream parlour following a fundraising event in Oregon on Saturday, Biden called the outcome “predictable” and said that while he disagrees with the Prime Minister’s strategy, it is up to the British people.

He also dismissed concerns about the strength of the dollar, saying: “The problem is the lack of economic growth and sound policy in other countries.”

The comments from Biden could lead to unwelcome headlines for the Prime Minister, as it is rare for the White House to appear to criticise a close ally.

Only a few weeks ago, a tweet Biden sent gave an indication of the gulf between his economic vision and that of the Prime Minister, when he said he is “sick and tired of trickle-down economics”.

Labour saw Biden’s latest comments and took them as further evidence of the damage the chaos of recent weeks has caused to the UK’s reputation.

Shadow foreign secretary David Lammy said: “As well as crashing the economy, Liz Truss’s humiliating U-turns have made Britain’s economy an international punchline.

“President Biden knows the dangerous folly of trickle-down economics.

“His comments confirm the hit our reputation has taken thanks to the Conservatives.

“We need a change in government.”

In recent years, prime ministers have often found themselves caught off-guard by comments from across the Atlantic and during Donald Trump’s time in office, it was a semi-regular occurrence.

Shortly after his election, Trump caused issues for then PM Theresa May when he suggested former Ukip leader Nigel Farage could become the UK’s ambassador in Washington.

In 2018, Trump used a visit to the UK to accuse May of ignoring his advice in her pursuit of a deal with the EU over Brexit.

In an interview with The Sun newspaper, he criticised her negotiating style, lavished praise on Boris Johnson and attacked her Brexit plan.

President Barack Obama also famously angered Brexiteers week before the important vote to leave the EU, telling the public that voting to leave would mean the UK would be at the “back of the queue” in any trade deal.