The King and Queen have left Buckingham Palace to cheers from the waiting crowds in The Mall as the moment of their coronation drew closer.
Charles and Camilla waved to thousands of spectators lining the street as leading figures began to join members of the congregation in Westminster Abbey.
The list of 2,300 invited guests reads like a who’s who of politics, showbusiness, world leaders and foreign royalty, with a sprinkling of everyday heroes and close family and friends of the King and his wife.
French President Emmanuel Macron was attending to show his “friendship, respect and esteem” for the UK, with US singer-songwriter Lionel Richie, The Repair Shop’s Jay Blades, and the Prince and Princess of Wales and their children.
The Duke of Sussex has arrived at the abbey, but the Duchess of Sussex has remained at home in the US.
The 33-minute journey to Westminster Abbey began with the tri-service Guard of Honour outside Buckingham Palace’s gates giving a royal salute, as the King and Queen’s Diamond Jubilee Coach first emerged, and the national anthem was played by a military band.
Huge Union flags and others from Commonwealth nations flew from poles in The Mall and Charles and Camilla’s route was lined by guardsmen in their distinctive red tunics and bearskins.
The Sovereign’s Escort was led by the Household Cavalry Mounted Regiment band, 48 horses and musicians with two drum horses Atlas and Apollo leading the way, playing eight marches along the route.
Following were four divisions from the Household Cavalry with the King’s coach in the middle – two from the Blues and Royals taking the lead and Life Guards behind the carriage with the farriers carrying their axes at the rear.
Crowds had been building up in the capital since dawn with the streets around the procession route – The Mall, Admiralty Arch, Trafalgar Square, Whitehall and Parliament Square – thronged with people.
The Duke of York was driven down The Mall in a state car, with parts of the crowd booing as he went past.
Celebrity guests arrived at the abbey, including actress Dame Emma Thompson, musicians Lionel Richie and Nick Cave and a cheery-looking Ant and Dec, in their smart morning suits.
Inside the ancient abbey, the church buzzed with noise as the congregation filed in and took their seats hours before the ceremony was due to start.
A smiling Dean of Westminster, Dr David Hoyle, in his vivid red clerical robe was seen hurriedly carrying the holy oil for the anointing down the length of the abbey from the altar through the quire, clutching the precious ornate silver vessel in both hands.
As anticipation mounted among royal fans, a group of republicans were arrested around 7.30am more than four hours before the coronation service began.
Footage on Twitter showed Graham Smith, chief executive of the anti-monarchy group Republic, being apprehended by police in St Martin’s Lane, Westminster.
Pictures appeared to show demonstrators in yellow “Not My King” T-shirts, including Mr Smith, having their details taken by officers.
Protest group Just Stop Oil also said approximately 13 demonstrators were arrested on The Mall, as well as five at Downing Street.
The King will be crowned during a coronation ceremony dating back centuries.
The senior cleric said in a statement issued on the eve of the coronation that the ceremony served as “a powerful reflection and celebration of who we are today, in all our wonderful diversity”.
He said people will be struck by the “majesty and sacred wonder” of the service, but also hoped they would find “ancient wisdom and new hope”.
But in a change, the controversial “Homage of the People” element of the service has been toned down after there was widespread criticism of the new element.
Mr Welby will now “invite” a show of support from the congregation rather than a “call” to those in the abbey and elsewhere to swear allegiance to the King.
The event will bring together around 100 heads of state, kings and queens from across the globe, celebrities, everyday heroes and family and friends of the couple, with Charles’ estranged son the Duke of Sussex expected to attend.
Invited guests include David and Victoria Beckham, King Willem-Alexander and Queen Maxima of the Netherlands, Prime Minister Rishi Sunak and US First Lady Jill Biden but her husband President Joe Biden will not be attending.
The day will be a display of pomp and pageantry, with the nation’s Armed Forces promising a “spectacular” event when the King and Queen process through the streets of the capital.
The event is the military’s largest ceremonial operation since Queen Elizabeth II’s 1953 coronation, with 9,000 servicemen and women deployed and 7,000 of these performing ceremonial and supporting roles.