It has been a tradition that has been honoured since the death of King George V in 1936, and again royal watchers are set to see the Vigil of the Princes being performed following the Queen's passing.
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On Monday, the late monarch will lie in state at St Giles Cathedral on Edinburgh’s High Street for 24 hours and members of the royal family, including King Charles III, will stand beside the coffin from 7.20pm in a tradition known as the Vigil of the Princes.
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The vigil refers to two occasions when male members of the British royal family "stand guard" - during the lying in state of a British state funeral or ceremonial funeral.
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It is highly likely that the late monarch's four children - King Charles III, Princess Anne, Prince Andrew and Prince Edward - will take their place around her coffin. If Princess Anne joins her brothers for the sombre occasion, she will become the first female royal to do so.
This tradition has only been performed twice, and was last carried out during the Queen Mother's funeral in 2002. That vigil was attended by the Queen Mother's four grandsons - the then-Prince of Wales, as well as Prince Andrew, Prince Edward and David Armstrong Jones, the 2nd Earl of Snowdon and Princess Margaret's son.
Royals performing the Vigil of the Princes for the Queen's Mother in 2002
Meanwhile, members of the public will be able to view the Queen's coffin at the cathedral and pay their respects from 5pm for a period of 24 hours.
On Tuesday, the Princess Royal will accompany the Queen's coffin when it is flown to London by RAF aircraft to RAF Northolt. The coffin will then be taken to rest at Buckingham Palace’s Bow Room.
A rehearsal for the procession of the coffin from Buckingham Palace to the Palace of Westminster is also expected to take place. Details about the route for the lying-in-state queue will be provided late on Tuesday.
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