The UK's top diplomat pointed to reforms by Britain's previous Conservative government to its foreign aid programme as "a big strategic mistake" which the new Trump administration should "look closely at".

In 2020 the UK government closed down the Department for International Development (DfID) and subsumed it into the Foreign Office, before slashing the aid budget the following year.

The moves earned widespread criticism at the time from aid groups and others in the sector, as well as the countries' opposition parties.

"What I can say to American friends is it's widely accepted that the decision by the UK with very little preparation to close down DfID, to suspend funding in the short term or give many global partners little heads up, was a big strategic mistake," Lammy told the Guardian.

"We have spent years unravelling that strategic mistake. Development remains a very important soft power tool. And in the absence of development... I would be very worried that China and others step into that gap," he added.

"So I would caution US friends to look closely at what went wrong in the United Kingdom as they navigate this decision."

Trump on Friday called for the United States Agency for International Development to be shut down, in an escalation of his unprecedented campaign to dismantle the massive government aid agency that has prompted confusion and chaos among its global network.

His administration has already frozen foreign aid and ordered thousands of foreign-based staff to return to the United States, with reported impacts on the ground steadily growing.