King Charles and Queen Camilla left Westminister Abbey in the Gold State Coach after their formal coronation ceremony on Saturday.
Pulled by eight horses, the 260-year-old coach will be cheered by crowds as it travels back along the 1.4 mile route to Buckingham Palace.
Named the Coronation Procession, the return leg features some 4,000 military officers.
Charles succeeded his mother Queen Elizabeth when she died last September and at 74, he has become the oldest British monarch to have the 360-year-old St Edward’s Crown placed on his head.
In the abbey, watched by about 100 heads of state and dignitaries, including U.S. first lady Jill Biden, and millions on television, Charles was crowned as his predecessors have been from the time of William the Conqueror in 1066.
For a nation struggling to find its way in the political maelstrom after its exit from the European Union and maintain its standing in a new world order, its supporters say the royal family still provides an international draw, a vital diplomatic tool and a means of staying on the world stage.
“No other country could put on such a dazzling display – the processions, the pageantry, the ceremonies, and street parties,” Prime Minister Rishi Sunak said.
Despite Sunak’s enthusiasm, the coronation is taking place amid a cost of living crisis and public scepticism, particularly among the young, about the role and relevance of the monarchy.
Saturday’s event is on a smaller scale than that staged for Queen Elizabeth in 1953, but still aimed to be spectacular, featuring an array of historical regalia from golden orbs and bejewelled swords to a sceptre holding the world’s largest colourless cut diamond.
Hundreds of soldiers in bright scarlet uniforms and tall black bearskin hats lined the route along The Mall, the grand boulevard to Buckingham Palace, where tens of thousands ignored the light rain to mass in a crowd more than 20 people deep in some places.
“I saw the beautiful white horses pulling the carriage,” said Beverlee Moag-Walker, 49, from Northern Ireland as the king’s carriage went past. “It was fabulous.”
Michelle Fawcett, 52, a barrister, said: “It was a moment in history and pretty spectacular.”
However, not all were there to cheer Charles, hundreds of republicans booed and waved banners reading “Not My King”.
More than 11,000 police are being deployed to stamp out any attempted disruption, and the Republic campaign group said its leader Graham Smith had been arrested along with five other protesters.
“It is disgusting and massively over the top,” said Kevin John, 57, who was among the anti-monarchy protesters.