US President Joe Biden has appeared to take a swipe at Liz Truss just a day before the pair meet in New York, as he publicly hit out at “trickle-down economics”.
Mr Biden said he was “sick and tired” of the theory that cutting taxes for businesses and the wealthy will see the benefits “trickle down” into the pockets of poorer workers.
His comments came after his British counterpart reiterated to broadcasters in New York that tax cuts were key to spurring economic growth across the UK.
Speaking to ITV News, Ms Truss also defended proposals to remove a cap on bankers' bonuses and admitted some of her measures "will be unpopular".
In a message on Twitter, Mr Biden said: “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.”
Critics of Ms Truss's low tax plans have widely slammed them as "trickle-down economics" - but the PM has insisted that the only way to grow the economy is to make it "competitive".
The two leaders will meet in New York on Wednesday, where they are both attending events as part of the United Nations general assembly.
His comments came as the prime minister and Chancellor Kwasi Kwarteng finalise a mini-budget on Friday.
This is expected to see previously planned increases in corporation tax scrapped and the hike in national insurance reversed, while also ending a curb on bankers’ bonuses.
While the message was presumably intended for a domestic US audience, it underlines the economic and political divide between the Democrat in the White House and the free-market Tory in No 10.
Ahead of her meeting with Mr Biden, the PM met with Emmanuel Macron in New York on Tuesday following frosty comments exchanged between the pair during her leadership campaign.
A Downing Street spokesperson said the "leaders agreed to enhance UK-France cooperation on energy to reduce volatility in the market and cut costs for households".
Despite Ms Truss not previously being able to determine if France was a "friend or foe", her spokesperson added: “The Prime Minister and President looked forward to strengthening our partnership with France and other likeminded European nations, including through the G7 and NATO.”
“The leaders welcomed the impressive advances made by the Ukrainian Armed Forces in recent days. They agreed on the importance of Ukraine’s friends and allies staying the course and supporting the country militarily, economically and politically," added Ms Truss's spokesperson.
“As our people face a difficult winter with huge uncertainty of energy supply and the cost of living, the Prime Minister and President Macron underscored the importance of working together to end reliance on Russian energy and strengthen energy security. We must continue to demonstrate to Putin that his economic blackmail over energy and food supplies will not succeed."
Their meeting came after after Ms Truss said the "jury was out" on whether France was a "friend or foe" during her leadership campaign - despite France being a long term ally.
Mr Macron later swiped back saying it was a "problem" if the UK cannot call itself a friend of France's.
“If the French and British are not capable of saying whether we are friends or enemies – the term is not neutral – we are going to have a problem," Mr Macron had said.
“So yes of course the British people, the nation which is the United Kingdom, is a friend, strong and allied, whoever its leaders are and sometimes in spite of the leaders and the small mistakes they can make in their speeches.”