The King’s right-hand man Sir Clive Alderton was sat next to Labour leader Sir Keir Starmer during a state banquet held in honour of the visiting Emperor and Empress of Japan.
Sir Keir is expected to be the next prime minister, according to polling ahead of the General Election, which has consistently put the politician’s Labour Party well ahead of their Conservative rivals.
The three-day state visit is the first time in living memory a foreign head of state has toured the UK as the nation prepared to go to the polls.
Also among the guests were Rishi Sunak and his wife and a number of senior members of the cabinet along with YouTuber Chris Broad, whose videos about life in Japan have proved a hit.
The close bond between the UK and Japan was praised by the King in a speech during the banquet, with Charles telling Emperor Naruhito and Empress Masako their “shared values of freedom, democracy and the rule of law” were more important than ever.
The King also spoke about his own personal connection with Japan and its head of state, telling the banquet guests how they both shared a passion for mountain climbing, and had spent time together at the opera and fly fishing.
Charles said in his speech: “At the core of our partnership is a close friendship; one based on a mutual understanding of the importance of international rules and global institutions, forged from the lessons of history, including its darkest years.
“Today, as we face a world in which these principles are ever more challenged, our shared values of freedom, democracy and the rule of law are more important than ever.”
“The seriousness and urgency of the climate and nature crises we face cannot be overstated, our generation owes it to those who follow to face it with vigour, determination and creativity.”
A Japanese Foreign Ministry official said the emperor and empress’s visit would not be a political one and it was hoped it would forge “friendly relations across generations” between Japan’s imperial family and the British royal family.
In 2017, a Spanish state visit by King Felipe VI was quickly rescheduled – after an agreement between the late Queen and King Felipe – because the date clashed with a snap election in the UK.
Among the royal guests at the banquet were the Prince of Wales, Duke and Duchess of Edinburgh, but missing was the Princess Royal who spent a second night in hospital after suffering minor head injuries and concussion after she was reportedly kicked by a horse on her Gatcombe Park estate on Sunday.
Camilla stepped out wearing the diamond-encased miniature portrait of her husband topped with a tiny gold and enamel Tudor crown and suspended on a pale blue silk bow on her left shoulder for the glittering event in the Buckingham Palace ballroom.
Guests dined on poached Scottish langoustines, baked fillet of Cornish turbot and an ice-cream bomb with peach sorbet.
After dinner, the banquet guests could try a yuzu marmalade sour, a cocktail featuring whisky and marmalade that resembled the flag of Japan.
Earlier, the visiting head of state and his wife received a ceremonial welcome on Horse Guards Parade and during the traditional carriage procession the empress, who has an allergy to horse hair, wore a face mask as a precaution.
