King and siblings to stand vigil around Queen's coffin - againpublished at 16:26 British Summer Time 15 September 2022
On Monday, King Charles and his siblings - the Princess Royal, the Duke of York and the Earl of Wessex - stood guard around their late mother's coffin in Edinburgh for 10 minutes.
Images showed the Queen's four children looking ahead or looking down, sometimes with their eyes closed.
They'll do the same tomorrow at Westminster Hall at 19:30 BST, carrying on a tradition called the Vigil of the Princes.
It started in 1936 after the death of King George V, when his four sons King Edward VIII, Prince Albert (the future King George VI and Queen Elizabeth II's father), Prince Henry and Prince George stood vigil around their father’s coffin in Westminster Hall.
When Charles, Princess Anne and Princes Andrew and Edward performed the same mark of respect on Monday, it was only the third time the Vigil of the Princes had been carried out - the second being at the Queen Mother's funeral in 2002. Anne also became the first woman in history to take part - note its name containing the word "princes".
In Edinburgh, members of the public were allowed to continue filing past the Queen's coffin while the royal siblings stood vigil. Buckingham Palace hasn't confirmed if the same will happen at Westminster, but it's expected it will.
They're due to stand for slightly longer this time - 15 minutes instead of 10 - so anyone queuing at the right time may get to see the historic moment.