Queen Elizabeth II on Sunday brought the curtain down on her historic Platinum Jubilee celebrations, making another public appearance on the last of four days of festivities and vowing to maintain her record-breaking reign.

The 96-year-old monarch, who has been troubled by mobility problems, appeared for the first time in person since Thursday on the Buckingham Palace balcony after the Trooping the Colour military parade.

Her exertions at the start of the celebrations had forced her to pull out of a thanksgiving church service on Friday, plus the Epsom Derby horse race and a star-studded concert on Saturday.

Huge crowds stretching hundreds of metres down The Mall outside the palace cheered as she re-emerged onto the balcony briefly on Sunday afternoon.

It followed a public parade reflecting changes in music, dance, fashion, culture and society since she came to the throne in 1952.

Dressed in green with a matching hat, her white gloved hand clutching a walking stick, she was flanked by the three future kings: princes Charles, William and George.

In a statement issued shortly after, the monarch said she had been "humbled and deeply touched" by the turnout for her Platinum Jubilee celebrations and "inspired by the kindness, joy and kinship that has been so evident in recent days".

Britain's longest-serving sovereign added: "While I may not have attended every event in person, my heart has been with you all; and I remain committed to serving you to the best of my ability, supported by my family."

Pageant

Sunday's £15-million ($18.7-million, 17.5-million-euro) "Platinum Jubilee Pageant", featuring some 10,000 people, began with a parade of armed forces from the UK and the Commonwealth she heads.

The queen's hologram was projected onto the sovereign's 260-year-old Gold State Coach that led the celebration of her reign.

Some 6,000 disabled and non-disabled performers joined in to celebrate the queen's life and reign.

Highlights included an aerial artist suspended under a vast helium balloon, known as a heliosphere, bearing the sovereign's image.

A carnival included a giant oak tree flanked with maypole dancers, a huge moving wedding cake, bangra drummers, steel bands, African-Caribbean carnival animals and a towering dancing dragon.

In the royal box, Charles kept his four-year-old grandson Prince Louis entertained, bouncing him on his knees to the rhythm of the music.

Singer-songwriter Ed Sheeran wrapped up the pageant with a rendition of his 2017 hit "Perfect", and the national anthem "God Save the Queen".

Elsewhere across the country, more than 10 million people are estimated to have braved overcast skies to share food with friends, family and neighbours to mark the occasion.

End of era

Two public holidays on Thursday and Friday, longer pub opening hours, street parties and other events have temporarily lifted the gloom of soaring inflation, political turmoil and two years of enforced Covid closures.

Many saw it as a once-in-a-generation event to mark the closing of an extraordinary chapter in British life and to recognise its most famous national symbol.

A peak of 13.4 million viewers watched Saturday night's concert on television, the BBC said.

During the celebrations, the queen put in a surprise on-screen appearance, taking tea with the beloved children's book and film character Paddington Bear, in a pre-recorded sequence that had been kept a carefully guarded secret.

She previously made a cameo with James Bond actor Daniel Craig for the opening of the London 2012 Olympics.

A running theme has been the dramatic social, political and technological changes in Britain and the world since the queen came to the throne -- and her constant presence through it all.

With Charles now 73, the next jubilee -- probably for his eldest son William's 25th year on the throne -- could be at least 50 years away.

"She's been the queen my whole life," said visiting American John Barli, 66.

"She's the world's grandmother as far I'm concerned," he told the Sunday Times.

But there was also acknowledgement the second Elizabethan era -- five centuries after the first -- is nearly over.

'Long goodbye'

A spectacular light show illuminated the palace and the night sky above it on Saturday, including images of a corgi, a handbag and a teapot.

One message said simply: "Thank you, Ma'am."

"Inevitably, this celebration had a valedictory feel," the Sunday Telegraph said of Saturday's concert.

"But there is also the keen awareness that we will never see the likes of this monarch again."

"It won't be the same without our queen," Julie Blewitt, 56, from Manchester, told AFP outside St Paul's Cathedral on Friday.

The Observer weekly called it "part of a long goodbye that began with her solitary attendance at Prince Philip's funeral last year".

The queen has gradually been preparing the public for the familiar figure of Charles to take over as king.

Yet the institution that Charles and, after him, William will lead will be different from the one Elizabeth inherited in the aftermath of World War II.

Then, Britain was still a major colonial power but republican movements are gathering pace in the 14 Commonwealth countries where the queen is also head of state, including Australia and in the Caribbean.

In her statement of thanks, Sunday, the queen said she hoped that the "renewed sense of togetherness" generated by the weekend's celebrations "will be felt for many years to come".

That hope seems unlikely to be realised.

Prime Minister Boris Johnson, struggling with the fall-out from "Partygate", the damaging revelations over lockdown breaches in Downing Street, was booed by the crowd at one of the Jubilee ceremonies this weekend.

He could face a no-confidence motion to topple him as soon as this week, according to some parliamentary observers.