EDINBURGH, Sept 13, 2022 (BSS/AFP) - Thousands of people queued throughout the night in Edinburgh on Tuesday to pay their respects to Queen Elizabeth II before her coffin was to be flown to London ahead of a state funeral.

Her eldest son and successor, King Charles III, will meanwhile visit Northern Ireland to meet political and religious leaders before a church service.

Charles, 73, is on a tour of all four nations of the United Kingdom to mark the start of his reign. He is due to visit Wales on Friday before the queen's funeral on September 19.

In Edinburgh on Monday evening, Charles and his three siblings held a 10-minute vigil beside their mother's coffin in Saint Giles' cathedral, as people paid their respects at the 12th-century place of worship.

Four members of the monarch's Scottish bodyguard, the Royal Company of Archers, stood heads bowed at each corner of the oak coffin.

It was draped in the Royal Standard of Scotland and topped with the ancient Crown of Scotland and a wreath including heather from Balmoral, the remote royal retreat where the 96-year-old head of state died peacefully last Thursday.

Images of the poignant, pomp-filled scene dominated the front pages of Britain's newspapers on Tuesday.

"The Queen's guard," headlined The Times, alongside a photo of a sombre-looking Charles.

- 'End of an era' -

Mourners queued for hours to file past the casket through the night. Waiting times were still roughly two hours at around 6:00 am (0500 GMT) and expected to lengthen through the morning, the Scottish government said.

One man, Gavin Hamilton from Edinburgh, queued for more than five hours and finally got inside the cathedral at 2:50 am, with thousands more behind him in the line.

"There were people in the queue with me who had travelled from Aberdeen, over 100 miles (160 kilometres) away, to do this," he added.

The queen's only daughter, Princess Anne, will accompany her mother's body later on Tuesday afternoon on the next leg of its journey by Royal Air Force jet to an airfield near London.

The huge crowds in Edinburgh are a sign of what can be expected in the capital in the build-up to the funeral.

The queen will first be driven to Buckingham Palace, then transferred to Westminster Hall on Wednesday, where she will lie in state for four days.

Earlier on Monday, Charles, again flanked by his three siblings, had led a procession on foot carrying the queen's body through hushed Edinburgh streets packed with mourners.

The queen's coffin had been driven on Sunday to the Scottish capital from Balmoral and held overnight at the royal residence of the Palace of Holyroodhouse.

Accompanied by kilted soldiers, the late queen was taken from the royal residence to the cathedral for a prayer service.

Thousands of people lined the route along the city's famous Royal Mile to watch the procession make its way to the ancient place of worship, as cannons fired at one-minute intervals from Edinburgh Castle.

The royals were joined by Prime Minister Liz Truss and Scottish First Minister Nicola Sturgeon at the service for the country's longest-serving monarch, who reigned for 70 years.

People who queued for hours spoke of their deep emotions after they finally got to file by the coffin.

"It's a real sense of connection to history -- and bear in mind that we're one of the few countries left with this sense of pageantry and connection to the past," said Rob Parsons, 28, after emerging from the cathedral.

"Seeing her obviously is a way of accepting the fact that it's the end of an era."

- 'Heartbreaking' -

Ahead of Charles's visit to Northern Ireland, people there expressed deep sadness at the queen's death.

"We've been followers of the royal family my whole life," said Christine Flynn, 37, paying her respects at Belfast's Platinum Jubilee mural, which has become a focus for mourners in the city.

"I think it's just very heartbreaking that we've lost the queen. It feels like a member of my family."

While large crowds are expected to welcome Charles in Northern Ireland on Tuesday, the visit to a deeply divided region still scarred by sectarian violence could prove testing.

Charles will meet Belfast's feuding political leaders -- split between fiercely loyal unionists and nationalists who want to reunify with Ireland -- before attending an Anglican religious service in the city.

The president, prime minister and foreign minister of Ireland are also set to attend.

- 'Unique event' -

Hundreds of thousands of mourners are expected in London to file past the queen's coffin at Westminster. The first arrived for the queue on Monday -- more than 48 hours before the line opens.

It is predicted to snake for several miles (kilometres) along the banks of the River Thames.

"It's going to be emotional and I don't know how I'll feel going in there as the first one," said Vanessa Nanthakumaran, a 56-year-old administration assistant originally from Sri Lanka.

"It's going to be a once-in-a-lifetime chance to be part of this unique event," she told AFP.

Britain is in 10 days of national mourning for Elizabeth II, who was a fixture of the nation's life and consciousness for seven decades.

Charles has seen his popularity recover since the death of his former wife Diana in a 1997 car crash. But he has also been embroiled in several scandals in recent years.

With republican movements gaining ground from Australia to the Bahamas, the new king faces a challenge keeping the Commonwealth realms in the royal fold.

New Zealand's prime minister, Jacinda Ardern, reiterated on Monday she believed her country would eventually become a republic.

"I believe it's likely to occur in my lifetime but I don't see it as a short-term measure or anything that is on the agenda anytime soon," she said.