US President Joe Biden paid emotional tribute to Queen Elizabeth on the eve of her state funeral on Sunday, saying Britain and the world had been lucky to have such a dignified and dedicated servant on the throne for 70 years.
Biden, among scores of dignitaries and royals from Europe, Asia, Africa and the Americas who have arrived in London for Monday's funeral, said the queen's death at 96 years of age had left a giant hole on the global stage.
"To all the people of England, all the people in United Kingdom, our hearts go out to you," Biden said after he signed a book of condolence and visited her lying-in-state in Westminster. "You were fortunate to have had her for 70 years, we all were. The world's better for her."
He said he had consoled the queen's heir, King Charles, that the queen would be "with him every step of the way, every minute, every moment and that's a reassuring notion".
Hundreds of thousands of people have descended on London to bid farewell to Britain's longest-reigning monarch, with people from all walks of life from around the country and overseas queuing for hours to file past her coffin.
Biden followed other world leaders in appearing on a balcony overlooking the coffin in the historic Westminster Hall, making a sign of the cross and placing his hand on his heart in reverence. French President Emmanuel Macron also appeared on the balcony.
The US president later joined Charles and other leaders for an evening reception ahead of the state funeral.
Biden was one of 14 US presidents in office during the queen's reign, of which Elizabeth met all except Lyndon Johnson, starting with Harry Truman in 1951 when still a princess.
He will join presidents, prime ministers, kings, queens and sultans representing nearly 200 countries and territories at the funeral.
Macron was seen walking near the River Thames earlier on Sunday, mingling with those gathered in the streets around parliament.
Liz Truss, who the queen appointed as Britain's prime minister two days before her death, took the opportunity to meet with leaders from Australia, New Zealand, Ireland, Canada and Poland over the weekend.
Saudi Arabia's Crown Prince Mohammed bin Salman, however, is no longer expected, according to a British government source. Inviting the man Western leaders believe ordered the murder in 2018 of Saudi journalist Jamal Khashoggi had been controversial. He has denied any role in the killing.
Britain has invited heads of state or ambassadors from any country with which it has full diplomatic relations, but it is up to those nations who they send. The change was made by Saudi Arabia, the source added.
'Love for a son'
For all the high ceremony and careful diplomacy of the funeral, for the queen's family it is also when they will bid farewell to a mother, grandmother and great-grandmother.
Prince Andrew, the queen's second son, paid tribute to "Mummy, Mother, Your Majesty" on Sunday, reflecting the roles he said Elizabeth fulfilled during her reign.
Andrew has fallen from grace, stripped of the "His Royal Highness" title and removed from royal duties after a scandal over his friendship with late US financier Jeffrey Epstein, a convicted sex offender, and a related sex assault allegation.
Andrew, Duke of York, has not been charged with any criminal offence and has denied wrongdoing. He paid to settle a US civil court case.
On Saturday, his two daughters joined the queen's other six grandchildren, including Charles' sons Princes William and Harry, at a vigil around her coffin.
Camilla, wife of the new king and now Queen Consort, said the smile of the late queen was "unforgettable", in her own tribute on Sunday.
Transport for London said it expected one million people in central London for Monday's funeral.
The period of mourning has already drawn hundreds of thousands of people to central London, many clamouring to view floral tributes and feel the atmosphere.
The government advised against travelling to join the queue to see the coffin before it closes later on Sunday.
Such has been the desire to pay tribute to the popular monarch, the only one most Britons have known since her accession in 1952, that tens of thousands have waited patiently for hours alongside the Thames to spend a few brief seconds at the side of her coffin.
Many have wept, said a prayer, bowed their head or dropped to their knees.
Dignitaries have also taken their place on the balcony to view her lying-in-state, with leaders from Canada, Brazil, Trinidad and Tobago and elsewhere having paid their respects.
Gary Thompson, 54, from London said: "When you're here, it's overwhelming."
New Zealand Prime Minister Jacinda Ardern said the "sheer silence" was one of the things that made the lying-in-state so moving, adding she had shared her moment on Friday with people who had queued for 20 hours or longer.
"The queen was here for her people and now her people are there for her," she told the BBC on Sunday.
Prince William joined his father Charles to speak to mourners waiting in line on Saturday. "She wouldn't believe all this, she really wouldn't," he said.
Moment of reflection
Britain has hosted a series of carefully choreographed ceremonies in the 10 days that have followed Elizabeth's death, reflecting the traditions and pageantry of a royal family whose lineage stretches back almost 1,000 years.
A minute of national silence was held at 8pm (1900 GMT) on Sunday, marked by the striking of Big Ben, which towers over Westminster Hall.
London's police force has described the funeral ceremony as the biggest security operation it has ever undertaken.
Members of the public were camping out to secure positions on the procession route and near Westminster Abbey, the site of coronations, weddings and burials of English and then British kings and queens since William I in 1066.
Britain has not held a state funeral on the scale planned for the queen since that for World War Two leader Winston Churchill in 1965.