The King has worn a black tie as a mark of respect to the Pope as he met the prime minister of New Zealand at Windsor Castle.
Charles, who is head of the Church of England, carried out his first official engagement since the death of the pontiff, the head of the Roman Catholic Church, on Easter Monday.
The King and New Zealand’s premier Christopher Luxon, who was also wearing a black tie, were said to have taken the opportunity to “reflect on Pope Francis’s remarkable life and legacy”, a source said.
Charles and the Queen had a moving private meeting with Pope Francis on their state visit to Italy, just 12 days before the 88-year-old died after a cerebral stroke.
The King has expressed his “most heartfelt condolences and profound sympathy” and praised Pope Francis’s compassion and tireless commitment to the common causes of all people of faith.
The monarch, who is also King of New Zealand, welcomed Mr Luxon to his Berkshire castle on Monday.
Mr Luxon is due to meet Prime Minister Sir Keir Starmer during his trip to the UK, with trade and security high on the agenda.
