Queen Elizabeth II's children guard coffin in solemn vigil

King Charles III and his three siblings stood guard around their mother Queen Elizabeth II's coffin on Friday in solemn vigil honouring Britain's longest-serving monarch.

The new king, Princess Anne, and Princes Andrew and Edward mounted the guard in silence around her flag-shrouded casket as members of the public, who had queued for hours, continued to file past.

The "Vigil of the Princes", with the royals all in ceremonial naval uniform, formed an emotionally-charged moment in London's mediaeval Westminster Hall, where Queen Elizabeth's coffin is lying in state ahead of Monday's funeral.

Her children stood with their heads bowed for 12 minutes as other members of the royal family including Queen Consort Camilla watched on and the public paid their own last respects.

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King Charles and his siblings mounted a similar vigil at St Giles' Cathedral in Edinburgh before the coffin was flown to London.

The Vigil of the Princes first took place in Westminster Hall in 1936 for king George V. His four sons, including Queen Elizabeth's father, stood guard.

Prince William and his brother Prince Harry will lead the queen's grandchildren in a similar vigil on Saturday evening.

Members of the public have been facing waits of up to 24 hours to file past the coffin.

Large crowds cheered King Charles and chanted "God Save the King" in the Welsh capital Cardiff earlier on Friday, as the new monarch shook hands with well-wishers following a multi-faith service in Llandaff Cathedral, and at Cardiff Castle.

Also Read | Queue to see Queen Elizabeth's coffin paused after reaching capacity

It was the last of his visits to the United Kingdom's four constituent nations following the death of Queen Elizabeth on September 8, at the age of 96.

Charles met in private with Welsh First Minister Mark Drakeford, an avowed republican.

In a speech at the Welsh Parliament, which alternated between English and Welsh, the king vowed to follow the "selfless example" of his mother.

Before ascending to the throne on September 8, Charles, 73, had been the Prince of Wales since 1958, a title bestowed on the heir apparent.

He made his eldest child William the new Prince of Wales on September 9.

Sharon Driscoll was in floods of tears after meeting King Charles at Cardiff Castle.

"It was very emotional, very personal, the eye contact meant a lot in view of how long we've waited," the 48-year-old nurse said.

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"I shook his hand and said 'I'm really sorry that your mum passed away'. He said 'thank you very much, it means a lot'," she said.

A handful of people used the occasion to protest against Britain's system of constitutional monarchy.

Outside Cardiff Castle, a few demonstrators held up banners declaring "Abolish the monarchy", "Citizen not subject" and "Democracy now".

Back at Buckingham Palace in London, King Charles reached out to Britain's various faith communities and pledged to defend freedom of worship under his reign.

On his accession to the throne, Charles became the titular head of the Church of England as its supreme governor, which comes with the title Defender of the Faith.

At his accession, he also pledged on oath to maintain and preserve the Protestant faith in Scotland.

He told assembled faith leaders that he was a "committed Anglican Christian" -- but believed that as sovereign it was his "duty to protect the diversity of our country, including by protecting the space for faith itself and its practise".

In 1994, he said he would rather see his future role as a defender of faith, rather than of the faith, but clarified in 2015 that the historic title was compatible with being a protector of freedom to follow other faiths.

Elizabeth's death has triggered an outpouring of emotion, with tens of thousands from all backgrounds and many nations queueing for hours, often through the night, to pay their respects in Westminster Hall.

The queue was paused for nearly an hour on Friday after a park at the end of the line along the River Thames reached capacity, the government said.

Then officials said just after 1600 GMT that the "expected queuing time is over 24 hours" -- up from 14 hours for those at the end of the queue.

They also warned of cold overnight temperatures and another pause if the line reached capacity.

David Beckham, the former England football captain, queued from 2:00am to pay his last respects.

Beckham, 47, wearing a dark suit and tie, stood with his hands behind his back, bowed his head towards the catafalque, then bit his lip before leaving Westminster Hall.

"It's very emotional, and the silence and the feeling in the room is very hard to explain," he told reporters afterwards.

"We're all there to say thanks to Her Majesty for being kind, for being caring, for being reassuring throughout the years.

"The legacy that she has left is incredible."

Also in the queue was Peter Stratford, 70, a former firefighter who was one of the first on the scene at a huge fire in 1992 at Windsor Castle, where the queen will be buried on Monday.

"My ankles are killing me, but it's a small sacrifice to make," he told AFP after waiting in line for eight hours.

"I've been tearful, emotional... I wouldn't have missed it."

Mourners marked their moment in front of the coffin in various ways, from bows or curtsies to the sign of the cross or by simply removing their hats, an AFP reporter inside observed Friday.

Some wiped away tears. Others brought infants in pushchairs. Old soldiers stopped and gave one last salute to their former commander-in-chief.

In a statement, the queen's youngest son Edward said her passing had left an "unimaginable void".

"We have been overwhelmed by the tide of emotion that has engulfed us and the sheer number of people who have gone out of their way to express their own love, admiration and respect to such a very special and unique person who was always there for us," he said.

"And now, we are there for her, united in grief. Thank you for your support. You have no idea how much it means."

At Westminster Abbey on Monday, the queen will be honoured with Britain's first state funeral in nearly six decades, with more than 2,000 guests expected.

After the televised service, the coffin will be transferred by royal hearse to Windsor Castle, west of London, for a private burial in which the queen will be laid to rest alongside her late husband Prince Philip, her parents and her sister.

Police are mounting Britain's biggest-ever security operation for the funeral, as global dignitaries jet in.

An official delegation from China has been banned from attending the lying-in-state following an intervention by House of Commons Speaker Lindsay Hoyle, parliamentary sources said.

It comes after China sanctioned several British lawmakers over their criticism of its human rights record.

"The British side should uphold both diplomatic courtesy and gracious hospitality," foreign ministry spokeswoman Mao Ning told reporters in Beijing.