US President Donald Trump and British Prime Minister Keir Starmer hailed the deepening of their nations' "special relationship" on Thursday, saying a raft of deals worth 250 billion pounds had made those bonds "unbreakable".

At the start of a business reception, some of the leading names in US and UK business were welcomed by the two leaders and praised for helping cement ties by investing in deals ranging from technology to energy.

It was the second day of Trump's unprecedented second state visit to Britain, which the US leader described as an "exquisite honour" after enjoying a day of pomp and ceremony, including a "fantastic" state banquet at Windsor Castle with King Charles.

Sitting next to each other in a marquee in the grounds of Starmer's Chequers country residence, Starmer and Trump celebrated the unveiling of a record 150 billion pound ($205 billion) package of US investment into Britain, part of a wider 250 billion pound package officials say will benefit both sides.

Trump hails 'unbreakable bond' with UK

"This is a great day for the special relationship," said Starmer, thanking the business leaders, including Nvidia's CEO Jensen Huang and GSK's Emma Walmsley.

"A celebration of what has gone before, of course, but more than that, a moment to deliver investments, jobs and deals which will improve people's lives now and light up the special relationship for years to come."

Trump was equally effusive. "The ties between our countries are priceless.

"We've done some things that financially are great for both countries ... I think it's an unbreakable bond we have, regardless of what we're doing today. I think it's unbreakable."

Starmer has pitched Britain as a destination for US investment, aligned to its financial services, tech and energy sectors so it can draw in US capital and build out its infrastructure and grow the economy.

He might have resigned himself to not getting any further reduction on steel tariffs, but he was keen to champion the wider deals, including a new technology pact with companies from Microsoft to Nvidia and OpenAI pledging 31 billion pounds ($42 billion) and 100 billion pounds from Blackstone.

Press conference not without perils

Earlier Starmer, standing alongside his wife Victoria, greeted Trump warmly at his Chequers country residence to the sound of bagpipes — a nod to the US leader mother's Scottish heritage — for a meeting which is not without perils.

Later on Thursday, the two leaders will hold a press conference, when journalists could quiz both over the late sex offender Jeffrey Epstein.

Starmer was forced to sack Peter Mandelson as ambassador to the US last week after his close ties with Epstein were documented and Trump's relationship with the late financier has also come under scrutiny.

"For Starmer, he is having a difficult domestic time and he needs a positive international narrative and to bring Trump on board on key issues," said Evie Aspinall, director of the British Foreign Policy Group think tank.

Trump would want to show there was value in close relations with Starmer, she said. "For both sides, they realise there is a lot to be gained."

Starmer will also hope that Trump's pride in attending the state banquet will deter the US leader from straying into more sensitive areas, such as Britain's online safety laws and position on Israel.

Speaking at Wednesday's banquet, Trump said Britain had "laid the foundations of law, liberty, free speech and individual rights" under its empire and "must continue to stand for the values and the people of the English speaking world".

A few hours later, he cheered the suspension of late-night host Jimmy Kimmel over comments made about the assassination of conservative activist Charlie Kirk. Trump has pressured broadcasters to stop airing content he finds objectionable.