US President Joe Biden has said he wasn't alone in thinking Liz Truss's economic plans "wouldn't work".
Mr Biden has been an outspoken critic of "trickle-down economics" but he has previously held back from criticising the Truss government.
However speaking to reporters in Oregon, he delivered a broadside to Downing Street, saying: "I wasn't the only one that thought it was a mistake
"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."
Before a meeting with Ms Truss last month, Mr Biden made the difference in their outlooks clear - but did not explicitly say he was talking about the UK.
It came as the PM was tipped to raise corporation tax, reverse the hike in national insurance and end a cap on bankers’ bonuses - which she and Kwasi Kwarteng then did in their disastrous mini-Budget.
Ahead of their meeting, Mr Biden tweeted: "I am sick and tired of trickle-down economics. It has never worked.
“We're building an economy from the bottom up and middle out.”
In response to the latest remarks, Labour's 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."
It comes as floundering Ms Truss fights for her future after sacking Mr Kwarteng on Friday.
Today, one of her backbenchers said she must apologise to the British people as her calamitous economic plans have left the public "frightened".
Education Committee chairman Robert Halfon accused his party of acting like "libertarian jihadists" and treating the country like "laboratory mice" for their hard line policies.
In a blistering intervention, Mr Halfon said the crisis-hit PM needed to perform a "dramatic reset" in the coming days.
He told Sky News: "I worry that over the last few weeks the government has looked like libertarian jihadists and treated the whole country as laboratory mice to carry out ultra, ultra free market experiments. And this is not where the country is.
"There's been one horror story after another."
