King Charles III will say the UK and France must stand together in the face of a "multitude of complex threats", when he speaks at a state banquet for French President Emmanuel Macron.

Macron and his wife Brigitte will be welcomed by the King and Queen and the Prince and Princess of Wales, as they arrive for a three-day state visit.

The state banquet will be a highlight of the trip, with famous faces, a showcase menu and a message from the King about the "shared history and culture between our two peoples".

This is the first state visit by the leader of an EU country since Brexit and the King will emphasise the need to work together on issues from military threats to climate change.

"For centuries our citizens have admired each other, amused each other, and imitated each other," the King will say at Tuesday evening's banquet, which will be held at Windsor Castle, as Buckingham Palace is being renovated.

He will warn of modern threats "emanating from multiple directions" and challenges that "know no borders" from which "no fortress can protect us".

"Our two nations share not only values, but also the tireless determination to act on them in the world," the state banquet speech will say.

A state visit is a "soft power" opportunity to strengthen partnerships, with the French visit set to reinforce links with the UK in trade, diplomacy and defence, at a time of uncertainty about the US stance on issues such as military backing for Ukraine.

A UK-France summit at Downing Street on Thursday, hosted by Prime Minister Sir Keir Starmer, is also likely to discuss ways of stopping illegal migration on small boats across the Channel.

The start of the visit on Tuesday will see ceremonial spectacles, with senior members of the Royal Family ready to greet the French visitors and to celebrate the "entente cordiale", in the first French state visit since 2008.

Prince William and Catherine will greet the French president and his wife when their plane touches down at RAF Northolt, with King Charles and Queen Camilla then welcoming them at Windsor.

There will be horses, as well as political horse-trading, with a carriage procession through Windsor, ahead of a royal salute and military parade at Windsor Castle.

On Wednesday, Macron will see a horse that he gave to the late Queen Elizabeth II, to mark her Platinum Jubilee in 2022.

The French president and his wife are also set to visit the tomb of the late Queen, during their stay in Windsor.

The UK government has spoken of wanting to "re-set" post-Brexit relations with European neighbours and Macron's visit will be a public endorsement of the longstanding alliance with France.

MPs and peers will be able to hear Macron when he gives a speech to the Houses of Parliament.

Advances in science will highlighted during the visit, with examples of artificial intelligence and innovative technology being shown to the French visitors at Imperial College London.

King Charles and Queen Camilla carried out a state visit to France in 2023, where he received a standing ovation for his speech to the French Senate.

He had given a strongly worded message of support for Ukraine after Russia's "horrifying" invasion. The King had also highlighted the "existential challenge" of climate change.