Queen Elizabeth II dies — follow the latest news as the world mourns
Her grandchildren were expected to be among members of the royal family paying their respects to the late monarch at the palace.
King Charles III and Queen Consort Camilla will be standing at the palace’s grand entrance, surrounded by the late monarch’s children and grandchildren and their partners, including the Prince and Princess of Wales and Duke and Duchess of Sussex.
The C-17 Globemaster aircraft arrived at RAF Northolt in north-west London after travelling from Edinburgh.
Soon after the large aircraft arrived at the military base, Princess Anne, who accompanied the queen’s coffin back to the capital with her husband Vice Admiral Sir Tim Laurence, issued a moving tribute to her mother.
Rehearsals for the procession of Queen Elizabeth's coffin in London - in pictures
The Princess Royal said she was “fortunate” to be able 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.
“We will all share unique memories. I offer my thanks to each and every one who share our sense of loss.”
The UK mourns Queen Elizabeth II - in pictures
Before the coffin was carried to a waiting state hearse, the princess royal and her husband left the military plane and stood with Chief of the Air Staff Sir Mike Wigston, while nearby was the Prime Minister Liz Truss and Defence Secretary Ben Wallace.
On parade was a guard of honour made up of service personnel from the Queen’s Colour Squadron of the Royal Air Force, who presented arms when the coffin was first seen.
The King’s Colour for the Royal Air Force was lowered in salute.
As the hearse carrying the coffin began its journey, people stood silently by the road with some recording the historic moment on their camera phones.