Leaders pay their respects to Queen Elizabeth II at Westminster Hall

Britain held a minute's silence in a final tribute to Queen Elizabeth II before her grand state funeral, after her son King Charles III welcomed world leaders at Buckingham Palace.

US President Joe Biden and French President Emmanuel Macron were among the stream of dignitaries who paid tribute at the late monarch's coffin.

The US president then attended a reception hosted by King Charles and the royal family for around 500 visiting dignitaries.

They included Japan's Emperor Naruhito, King Felipe VI of Spain, Brazilian President Jair Bolsonaro, King Abdullah II of Jordan and Queen Margrethe II of Denmark.

The minute of silence was held to honour the late queen's life of service.

Prime Minister Liz Truss stood in a black dress outside her 10 Downing Street official residence for the "national moment of reflection" before the eyes of the world focused on the British capital for the queen's send-off.

Members of the public have camped out in advance to catch a glimpse of the grand farewell at Westminster Abbey, which is expected to bring London to a standstill and be watched by billions of viewers across the globe.

Australia's anti-monarchy Prime Minister Anthony Albanese, who viewed the lying-in-state and met King Charles, said that the queen was "a constant reassuring presence".

There was also a private audience at Buckingham Palace for New Zealand PM Jacinda Ardern, which, like Australia, Britain and 12 other Commonwealth realms, now has King Charles as its sovereign.