US President Donald Trump will make an unprecedented second state visit to Britain in September, with confirmation he will be hosted by the King and Queen at Windsor Castle.

Trump – a big supporter of the royal family – will be accompanied by his wife Melania during the three-day visit from September 17 to 19, Buckingham Palace announced on Monday (local time).

It is the first time a US president has been invited for a second state visit.

Trump previously enjoyed the pomp and pageantry of the state visit in 2019 during his first term when he was hosted by Queen Elizabeth II.

The invitation for this visit was hand-delivered by British Prime Minister Keir Starmer in February during a meeting at the White House.

Trump said it was a “great, great honour” and appeared particularly pleased by the fact he will stay at Windsor Castle.

“That’s really something,” he said.

While the full program of events for the visit is yet to be announced, it will – like all visits of this kind – include a full ceremonial welcome and a state banquet (to be held in St George’s Hall in Windsor Castle).

State visits normally focus on central London and Buckingham Palace. But with it undergoing extensive remodelling, the Trumps will stay at Windsor Castle – as French President Emmanual Macron and his wife Brigitte did for their visit last week.

All senior members of the royal family will again be involved in the Trump visit, including the Prince and Princess of Wales.

However, Trump will be denied the opportunity to address the British Parliament because the House of Commons will not be sitting at the time.

Precedent for second-term US presidents who have already made a state visit is usually tea or lunch with the monarch at Windsor Castle, as was the case for George W Bush and Barack Obama.

State visits are ceremonial meetings between heads of state that are used to honour friendly nations and sometimes smooth relations between rivals.

While the King formally issues the invitation for a state visit, he does so on the advice of Britain’s elected government.

The visit is seen as part of Starmer’s effort to keep Trump close and lessen the impact of some of his polices on Britain.

The relationship between the two appears amicable and has helped Britain avoid being slugged with the sort of hefty US tariffs that other nations are facing.

The Trump blimp in London in 2019. Photo: CrowdSpark/See LI

Like Trump’s previous visit, it’s unlikely he will be welcomed by all. Last time, there was a day of protests that included a giant blimp depicting Trump as an angry orange baby flying outside the Houses of Westminster.

MPs from Starmer’s Labour Party have also questioned whether the honour should be extended while Trump supports Israel’s war in Gaza and is threatening the sovereignty of allies such as Canada and Greenland.

The King could also face some challenges because he is head of state of both Britain and Canada, which Trump has repeatedly suggested should become the 51st US state.

During a speech to the Canadian parliament in May, the King highlighted Canada’s “unique identity” and “sovereignty”, while echoing the words of the country’s national anthem when he said “The True North is indeed strong and free”.

State visits to Britain are particularly prized by heads of state because they come with a full complement of royal pomp and circumstance, including military reviews, carriage rides and a glittering state banquet hosted by the monarch.

-with AAP