Britain’s King Charles heads to the United States next week for the most high-profile trip of his reign so far, on a mission to shore ​up the future of the two allies’ “special relationship” which the Iran war has plunged to its lowest point in 70 years.

The state visit marks the 250th ‌anniversary of the US declaration of independence from British rule, when the then 13 American colonies decided to split from King George III, Charles’s five-times-great-grandfather.

For Charles, it will be a moment to reflect on how Britain and the United States have come together since then to forge some of the world’s closest security, military and economic ties, while for US President Donald Trump it will be another chance to indulge his ​love of the British royals.

Worst Crisis Since Suez

It also comes against the backdrop of the worst relations between the two countries since the Suez Crisis in 1956, ​with repeated criticism by Trump of Prime Minister Keir Starmer over his refusal to join the attack on Iran and dismissive remarks about Britain's military capabilities.

Nigel Sheinwald, Britain’s ambassador to Washington from 2007 to 2012, said the visit could not, and was not designed to heal any current acrimony between governments, but it ​would demonstrate ties that went far deeper than any individuals.

“Pretty much more than any other visit, this is about the long term. This is about the fundamentals of the relationship between ​our peoples, our countries,” Sheinwald told Reuters. “It’s not about what’s going on today.”

Charles, accompanied by his wife Queen Camilla, will kick off the four-day trip on Monday with a private tea with Trump before addressing Congress, a state dinner and visits to New York and Virginia.

Buckingham Palace has said he will not be meeting any survivors of Jeffrey Epstein. Charles’ brother, Andrew Mountbatten-Windsor, was arrested in February on suspicion of ​leaking government documents to the late US sex offender.

The former Prince Andrew has denied any wrongdoing.

Back in Britain, some politicians and commentators have said the trip should have been ​cancelled given some of the recent remarks from Trump. There are also fears the unpredictable US president might use the occasion to deliver further criticisms and so potentially embarrass the king.

Sheinwald and the current ‌US ambassador to London, Warren Stephens, have said that it would be damaging. Royal aides privately say Trump, who calls the king a “great man”, behaved impeccably during his unprecedented two-state visits to Britain in 2019 and last year.

“He is a huge royalist,” royal biographer Robert Hardman told Reuters.

“He has ... one mindset when it comes to the British government, but the British monarchy is a completely separate element, and he’s a huge fan of it. And he adored the late queen, a big fan of the king. For him, this is a big moment.”

Echoes of 1957?

In some ways, ​Charles’ trip has echoes of the one ​made by his mother, Queen Elizabeth, in 1957, a year after the Suez Crisis caused upheaval in the Middle East, with British, French and Israeli troops forced to end an invasion of Egypt after pressure from the United States.

Her visit then succeeded in winning over US President Dwight Eisenhower and smoothing relations between ​the allies.

“The respect we have for Britain is epitomised in the affection we have for the royal family, who have honoured ​us so much by making this visit to our shores,” Eisenhower said.

It is this so-called “soft power” that Charles, who has honed his own diplomatic skills over half a century, will again be seeking to deploy.

Such is his power to sway the president that Hardman said he understood Trump rowed back on comments he made about British and other NATO troops staying off the frontline in Afghanistan after receiving private messages from the king ​that he was wrong.

In their private meeting, Charles will be again able to speak frankly, diplomats say, ​but Hardman said the king was not there to “pick holes in President Trump’s policies.”

“That’s just simply not the role of a monarch, and it’s certainly not the purpose of a state visit,” Hardman said. “This will be all about ​looking back on all those ... shared endeavours between two great allies and ... looking forward, possibly try to ... not look too closely at the present.”