World leaders begin gathering in London for the funeral of Queen Elizabeth II from Saturday, as Princes William and Harry will lead a vigil of their grandchildren at her coffin.

The Queen’s death on September 8 at the age of 96 after a record-breaking 70 years on the throne has sparked an outpouring of emotions.

Members of the public braved waits estimated at one point to be up to 24 hours and cool nighttime temperatures to see her coffin.

Lines have snaked for miles along the River Thames since Wednesday, when her coffin was taken to Britain’s Houses of Parliament to be laid out in state.

Police are conducting the UK’s biggest security operation yet for Monday’s funeral, as hundreds of dignitaries including US President Joe Biden are flown in.

The Queen’s successor, King Charles III, is set to meet the Prime Ministers of the Commonwealth realms – the 14 former colonies he now rules in addition to Britain – on Saturday.

From Australia and New Zealand to Canada, they have officially declared him their new sovereign.

But republican movements are gaining ground, and efforts to keep them all in the royal fold will likely be a feature of his reign.

Charles ended his first tour as monarch to the four nations of the United Kingdom on Friday with a visit to Wales, part of an operation called Spring Tide to usher him into his new role.

Large crowds in Cardiff chanted “God save the King” as he shook hands with well-wishers after a multi-religious service at Llandaff Cathedral and Cardiff Castle.

Charles met Welsh First Minister Mark Drakeford, a self-confessed Republican, and there were scattered boos in the streets after the new monarch was quick to proclaim his son William the new Prince of Wales.

But Drakeford said questions about the future of the monarchy were “a footnote to the prevailing sentiments of the day”.

Back in London on Friday night, Charles held a 15-minute vigil with his siblings – Princess Anne, Prince Andrew and Prince Edward – around their mother’s coffin.

They stood, eyes downcast, in silence while members of the public walked by.

Andrew – who was stripped of his royal titles this year over a sexual assault scandal – has been allowed to wear a military uniform for the only time during the 11-day mourning period.

The Duke of York, as he is also known, flew Royal Navy helicopters with Argentina during the 1982 Falklands War.

The vigil will be repeated on Saturday night by eight of the Queen’s grandchildren, including the new heir to the throne, Prince William, and his estranged brother, Harry.

Harry – who served on two deployments with the British Army in Afghanistan – has also reportedly been given special permission to wear his military uniform despite no longer being a working royal.

The move appeared to be the latest olive branch offered to Harry by the royals after he and his wife Meghan raised accusations of racism in interviews from their new home in the US.

The Queen’s family’s personal grief is being played out in the glare of intense international attention.

But the Queen’s youngest son, Edward, said: “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. “

The most striking manifestation of public reverence for the Queen was the huge lines of hundreds of thousands of people wanting to bid her farewell.

Officials warned Friday that the expected wait had been more than 24 hours, and briefly suspended entry when the lines were reaching capacity.

Among those who paid their respects was former England football captain and fashion icon David Beckham, who took 12 hours to reach Westminster Hall.

“It’s very emotional and the stillness and the feeling in the room is very difficult to explain,” he told reporters after walking past the coffin.

“We’re all here to thank Her Majesty for being kind, caring and reassuring over the years.”

June Nayler, 76, a retired local government worker from Milton Keynes in central England, was undeterred by the long wait she faced when queuing at Southwark Park.

“I’m here now and I’ll make it to the end – it’s my duty to do it,” she told AFP.

“I’m just blown away by the crowd and the number of people coming out.”

The public has until Monday morning to view the coffin before the Queen is honored with Britain’s first state funeral in almost six decades.

At the spectacular ceremony at Westminster Abbey, expected to be watched by millions around the world, 142 sailors will pull the gun carriage carrying their lead-lined coffin.

More than 2,000 guests will attend, but leaders from countries at odds with Britain, such as Russia, Belarus and Afghanistan, have not been invited.

A funeral service will be followed by a private funeral at Windsor Castle.