King Charles, his siblings, and princes William and Harry have gathered at Buckingham Palace to receive the coffin of the late Queen Elizabeth.
On a night of heavy rain, the well-lit hearse drove through London's suburbs from RAF Northolt, where the Queen's coffin arrived after being flown from Edinburgh on Tuesday afternoon, local time.
Tens of thousands of people lined the route, some throwing flowers.
A palace spokesperson said Charles, who automatically became king on the death of his mother last week, met the hearse alongside Princess Anne, Prince Edward, Prince Andrew, Prince William and Prince Harry, as well as other senior members of the royal family.
As the hearse arrived, the King could be seen through the palace window with his head bowed.
Prince Harry and his wife Meghan, Duchess of Sussex, were behind him.
Earlier in the day, the coffin was driven from St Giles' Cathedral to Edinburgh Airport and loaded onto a Royal Air Force aircraft.
UK Prime Minister Liz Truss, Defence Secretary Ben Wallace and a military honour guard were among those greeting the coffin when it arrived at the west London RAF base.
The coffin has now been taken to Buckingham Palace, where it will rest in the Bow Room overnight.
Princess Anne, the Queen's only daughter, escorted the coffin on the flight back to London.
In a statement, the Princess Royal thanked those who had offered their condolences for the loss of her mother.
"I was fortunate to share the last 24 hours of my dearest Mother's life. It has been an honour and a privilege to accompany her on her final journeys," she said.
"Witnessing the love and respect shown by so many on these journeys has been both humbling and uplifting."
More than 5 million people tracked the flight from Edinburgh to RAF Northolt, according to the Flightradar24 website.
Flightradar24 said 4.79 million people watched the flight live online, with a further quarter of million people watching on its YouTube channel.
Earlier King Charles III made his first trip as King to Northern Ireland, with Queen Consort Camilla at his side.
The royal couple were greeted by Northern Ireland Secretary of State Chris Heaton-Harris on arrival in the capital Belfast before they headed to Hillsborough Castle, the official royal residence, where they were met with cheers and applause from wellwishers.
During a signing ceremony at Hillsborough Castle, the new King lost his temper in front of cameras when a pen leaked on his hand.
It was the second time in recent days the King became frustrated when signing documents.
He flew back to London later to receive the coffin with his family.
As the new King tours his kingdom, some public events and locations have attracted protesters holding pro-republic and anti-monarchy signs.
On Wednesday, a procession with the King's Troop, Royal Horse Artillery, will take the Queen's coffin from Buckingham Palace to Westminster Hall where the Queen will lie in state for four days.
The procession will pass The Mall, Horse Guards, Whitehall, Parliament Square and New Palace Yard before it arrives at Westminster Hall.
ABC/wires
