What is the Vigil of the Princes that royals perform beside Queen’s coffin?

Last such vigil took place in 2002 when Queen Mother died and lay in state at Westminster

Shortly after midnight on 28 January 1936, the then King Edward VIII and his three brothers – Princes Albert, Henry and George – filed quietly into Westminster Hall and, in full military uniforms, stood guard at the coffin of their late father, King George V.

All day the public had been paying their respects to the passed monarch but these 15 minutes were reserved solely for his sons.

It was, royal experts have since said, a last, personal goodbye to their departed father.

The Prince of Wales standing vigil beside the Queen Mother's coffin while it lay in-state at Westminster Hall in 2002 (PA)

Thus, began the Vigil of the Princes, a new royal tradition which is expected to be continued in the coming days.

As part of Operation London Bridge – the official plans for the Queen’s funeral – it is said that this special moment will once again be recreated while Elizabeth II lies in state.

On Monday (12/9), it is believed the late monarch’s four children – King Charles III, Princess Anne, Prince Andrew and Prince Edward – and her eight grandchildren, including Princes William and Harry, 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.

The historic ceremony will occur while the Queen liesin state at St Giles' Cathedral in Edinburgh.

Charles, now King, will be joined by his siblings at the service (PA Wire)

It will be third such Vigil of the Princes.

The second occurred following the death of the Queen Mother in 2002. At 4.40pm on 8 April of that year, her four grandsons Prince Charles, Prince Andrew, Prince Edward and David Armstrong-Jones, took their place at her side in Westminster Hall.

Prince Andrew, Prince Edward and Princess Anne are all expected to take part (AP)

On that occasion, not even the guards stayed in the room with the Royal Company Archers dismissed for the private 20 minutes.

The Queen herself will lie-in-state in Edinburgh from 5pm on Monday to 5pm on Tuesday when she will be transferred to London.

A lying-in-state will then begin in Westminster Hall on Wednesday and last four days before her funeral on Monday 19 September.