Heraldo de Madrid - Four-kilometre queue as mourners file past Queen Elizabeth's coffin

At the head of the four-kilometre (2.4-mile) queue, well-wishers had camped out for 48 hours in order to pay their respects in front of the flag-shrouded coffin which was brought from Buckingham Palace earlier in the day.

"Inside it was really quite calm and incredibly emotional. A lot of people were in tears, but there was total silence," 50-year-old accountant Sue Harvey said after emerging from the hall.

"She is everything I have known. I wanted to make sure I did see her, no matter how long the queue was going to be," she told AFP.

In sombre scenes, many people stopped and bowed or curtsied towards the coffin. Others crossed themselves, or removed their hats.

Some prayed towards the casket or wiped away tears with tissues. Some brought their infants in pushchairs. Old soldiers stopped and gave one last salute to their former commander-in-chief.

To the strains of a military band playing funeral marches, King Charles III led the royal family in procession to Westminster Hall behind a horse-drawn gun carriage bearing the coffin.

The new king, his siblings, and sons Princes William and Harry, walked at 75 steps a minute behind the gun carriage as the Big Ben bell tolled from the Elizabeth Tower at the Houses of Parliament, and guns fired regular salutes from Hyde Park.

The lying-in-state began with a short Anglican service before black-clad members of parliament including new Prime Minister Liz Truss filed past the coffin, which will be on display for five days, around-the-clock.

"Nobody wants to wait, but we kind of feel that we owe something to the queen because she's been there for the whole of our lives," said Andrew Clyde, 53, who had travelled specially from Northern Ireland.

"I'm ready to wait the whole night if I need to."

- Endurance test -

The grand procession through the flag-lined heart of London represented the latest step in 11 days of intricately choreographed national mourning that will culminate with the funeral on Monday of the longest-reigning monarch in British history.

The sight of the new king's two grief-stricken sons inevitably evoked memories of 1997, when William and Harry, then aged just 15 and 12, walked, heads bowed, behind the coffin of their mother, Diana, princess of Wales.

But it comes with the once-close brothers now estranged, after Harry left royal duty and moved to California with his US wife Meghan.

The public have been warned they will face an endurance test to see the queen's coffin with lines that could tail back a maximum 16 kilometres.

Waiting in line earlier in the day, Brian Flatman, 85, said there was "no way" he would pass up the chance to pay his respects, having missed the queen's coronation in 1953.

"I was 16, we got there before midnight, Hyde Park Corner, superb position, but very quickly I became suddenly ill and had to crawl all the way to south London," he recalled.

"This time there is no way I can miss that. I will dedicate a few seconds there (by the coffin) to her life of dedication. What an example."

Strict rules and airport-style security measures are in place, with "far more" people expected than the 200,000 who filed past the coffin of the queen's mother when she died in 2002, according to the government.

"It's a massive challenge for the Metropolitan Police and for me personally, but we have been preparing for many, many years," Mark Rowley, the newly-appointed head of the London police force, told Sky News television.

- UK tour -

The body of the late 96-year-old queen, who died "peacefully" at her remote Balmoral estate in Scotland on Thursday, was flown to London aboard a military transport plane on Tuesday from the Scottish capital Edinburgh.

It was then driven to Buckingham Palace, past crowds of motorists who stopped their vehicles at the side of the road to catch a glimpse of the coffin, lit up inside a specially-built hearse.

The London procession on Wednesday mirrored a similar ceremony in Edinburgh on Monday when her coffin was driven through the hushed streets of the city to lie at rest at St Giles' Cathedral.

There, some 33,000 people filed past the coffin, the Scottish government said.

After Scotland and England, Charles continued his tour of the four nations of the UK on Tuesday by visiting Northern Ireland for the first time as king. He visits Wales on Friday.

The 73-year-old new head of state has won wide praise in the British media for his dignified and often heartfelt reaction to his mother's death, which has led to a rare moment of public unity in Britain.

He has seen his popularity recover since the death of his former wife Diana in a 1997 car crash -- and his ratings have surged in recent days, according to a survey on Tuesday.

The mourning has also obscured -- albeit briefly -- the broader country's sharp political divisions and a severe cost-of-living crisis that is expected to cause a major increase in poverty over the coming winter.

- No invite for Putin -

Not everyone shares the public mood of sadness and remembrance sparked by the queen's death, with royal fatigue increasingly evident on social media in the face of blanket media coverage.

British police have also faced criticism from civil liberties groups over their treatment of anti-monarchy protesters who have publicly challenged King Charles's accession to the throne.

Video footage and witnesses have drawn attention to police arresting or intimidating people who shouted slogans against the monarchy or held up placards reading "Not My King".

Queen Elizabeth's funeral will take place in Westminster Abbey, next to parliament, in front of 2,000 VIP guests, with the day declared a public holiday in Britain.

Hundreds of heads of state and government, as well as global royalty, are expected, but Russia, Belarus and Myanmar have not been invited to send representatives.

Biden spoke to King Charles for the first time since the queen's death on Wednesday, urging a continued "close relationship," the White House said.

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