George Osborne has appeared to back Hillary Clinton's bid to become US president in an escalation of Downing Street's row with rival candidate Donald Trump.
In a departure from the usual diplomacy shown when discussing foreign elections, the Chancellor told ITV's Peston On Sunday: "We look forward to working with whoever the next president is, whoever she may be."
Mr Osborne also described the billionaire businessman as "odd" when discussing politicians who want Britain to leave the European Union.
He said: "It's becoming quite an odd collection of people who support Brexit around the world, isn't it?
"It's Marine Le Pen and Donald Trump and we've got George Galloway and Nigel Farage."
His comments follow David Cameron's refusal to withdraw his condemnation of Mr Trump's call to ban Muslims from the US as "divisive, stupid and wrong".
An adviser to Mr Trump had called on the Prime Minister to apologise to Mr Trump, after the withdrawal of main rival Ted Cruz made him all but certain of securing the Republican nomination.
But Mr Cameron said he would not "add or subtract" from his comments, while No 10 made clear he had "no intention" of withdrawing them.
Downing Street has previously confirmed that Britain's ambassador in the US has been "engaging" with Mr Trump's team as "part and parcel" of the UK's usual efforts to establish good links with presidential candidates.
Prime ministers are traditionally wary of making any public comment about candidates in elections overseas, for fear that they may be accused of attempting to interfere in the democratic decisions of foreign nations, or that their words may come back to bite them if they later have to deal with the candidate in office.
At the time of Mr Cameron's criticism, Mr Trump was widely regarded as a maverick candidate who would struggle to translate his popular appeal into a Republican nomination or a credible bid for the White House.
But now he looks set to take on Mrs Clinton in the race to become the next occupant of the White House.