US President Donald Trump has raised a disagreement with British Prime Minister Keir Starmer during a largely cordial final press conference on his historic state visit.

After two days in Britain, which the US leader described as an “exquisite honour”, Trump was in a relaxed mode at his final engagement on Thursday (local time).

The two leaders glossed over differences on the Gaza Strip and wind power to present a united front.

Trump said Russian President Vladimir Putin had “let him down” and he was disappointed other countries were still buying Russian oil because only a low oil price would punish the Kremlin.

Trump raised a “disagreement” he had with Starmer on recognising Palestine. Starmer has said the UK will do so unless Israel relieves suffering in the Gaza Strip and reaches a ceasefire in its nearly two-year war with Hamas.

“I have a disagreement with the Prime Minister on that score, one of our few disagreements, actually,” Trump said.

Neither leader was tripped up by potentially embarrassing subjects, with both batting away questions over late sex offender Jeffrey Epstein and his ties to Trump and to Starmer’s former ambassador to the US.

“We’ve renewed the special relationship for a new era,” Starmer said.

“This partnership today is a signal of our determination to win this race together and to ensure it brings real benefits in jobs, in growth, in lower bills, to put more hard-earned cash in people’s pockets at the end of each month.”

Trump also paid homage to the two countries’ close ties, saying Starmer was a tough negotiator in securing the first tariff deal with the US, although Britain still does not have the lower US tariffs on steel that it had sought.

“We’re forever joined and we are forever friends and we will always be friends,” Trump said.

Trump, Melania Trump, Keir and Victoria Starmer as the Trumps depart the PM’s country estate. Photo: AAP

Earlier, at the start of a business reception, some of the leading names in US and UK business were welcomed by the two leaders to unveil a record £150 billion ($309 billion) package of US investment into Britain, part of a wider £250 billion package officials say will benefit both sides.

Starmer said the deals would “light up the special relationship for years to come”.

Trump was equally effusive.

“The ties between our countries are priceless,” he said.

“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.”

When the final question was answered, a clearly relieved Starmer ushered Trump out of the Great Hall at Chequers before the President left to return to Washington DC.

Trump and Starmer view an air force display over Chequers. Photo: AAP

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 to grow the economy.

He was keen to champion deals including a technology pact with companies from Microsoft to Nvidia and OpenAI pledging £31 billion and £100 billion from Blackstone.

In terms of any differences, it was on foreign affairs where the two were most out of lockstep.

Starmer, and other European leaders, have pressed Trump to put more pressure on Putin to end his war against Ukraine; Trump, while criticising the Russian president, failed to mention any further sanctions against Russia.

The US leader again expressed frustration that European countries were still buying Russian oil, but said Britain was not among them.

-with AAP