King Charles welcomed French President Emmanuel Macron to Britain on Tuesday for the first state visit by a European leader since Brexit, their warm greeting symbolising the return of closer ties between the two countries.
Macron, treated to a British state visit for the first time, enjoys a strong personal relationship with the king, and there were smiles as the pair met alongside their wives, Brigitte and Queen Camilla, and watched over by soldiers on horseback, in ceremonial uniform of blue tunics and scarlet plumes.
Charles is expected to emphasise "the multitude of complex threats" both countries face in a speech he will deliver at a state dinner at Windsor Castle later, while Macron posted on X on his arrival that "there is so much we can build together".
Kicking off the trip in that spirit, the two countries jointly announced that French nuclear energy utility EDF would invest £1.1 billion ($1.5 billion) in a project to build a nuclear power station in eastern England.
In Windsor, accompanied by heir to the throne Prince William and his wife Princess Catherine, the group climbed into several horse-drawn carriages for a procession which finished in the medieval castle's courtyard, west of London.
Since Prime Minister Keir Starmer's centre-left Labour Party swept back to power last year, Britain has been trying to reset ties with its European allies, and Charles will help set the tone of Macron's visit before the political talks get underway.
"Our two nations share not only values, but also the tireless determination to act on them in the world," the 76-year-old monarch, who is still undergoing treatment for cancer, will say at the banquet later.
While Macron's three-day trip is filled with talks on economic issues and foreign affairs, the first day of the state visit, which comes 16 years after the late Queen Elizabeth hosted then French president Nicolas Sarkozy, is largely focused on pageantry, and heavy in symbolism.
The monarch's right eye was noticeably red when he met Macron. A Buckingham Palace source said he had suffered a burst blood vessel in one eye which was unrelated to any other health condition
Macron is due to address the British parliament in central London later on Tuesday before heading back to Windsor Castle for the state dinner, where he and the king will speak before some 150 guests.
"It's wonderful that we're going down the path of welcoming European leaders once again," Alastair King, the Lord Mayor of the City of London, who will host a banquet in Macron's honour on Wednesday, told Reuters.
MIGRANTS DEAL
Later in his trip, Macron and Starmer's discussions will focus on a range of issues, including how to stop people-smuggling and improve economic and defence ties at a time when the United States is retrenching from its traditional role as a defender of European security.
Although there have been tensions over the shape of post-Brexit ties and how to stop asylum seekers from crossing the Channel in small boats, Britain and France have been working closely together to create a planned military force to support Ukraine in the event of a ceasefire with Russia.
British officials are hoping that Macron will agree to a pilot of an asylum seekers' returns deal. This would involve Britain deporting one asylum seeker to France in exchange for another with a legitimate case to be in Britain, thereby disrupting the business model of people-smuggling gangs.
A record number of asylum seekers have arrived in Britain on small boats from France in the first six months of this year.
Starmer, whose party is trailing behind Nigel Farage's right-wing Reform UK party in the polls, is under pressure to come up with a solution.
France has previously refused to sign up to such an agreement, saying Britain should negotiate an arrangement with all EU countries.