The Prince of Wales and Duke of Sussex have joined their cousins in a solemn vigil at their beloved grandmother’s coffin.

Brothers William and Harry – both dressed in uniform – stood guard at the Queen’s lying in state in Westminster Hall on Saturday evening as a stream of mourners filed past after queueing for hours.

Harry, who saw action on the front line during two tours of duty in Afghanistan, has previously been denied the chance to wear his military uniform as he publicly mourns, because he is no longer a working royal.

But royal sources said the King decided his youngest son could wear uniform for the vigil.

Despite being a former Army officer, Harry has been in civilian dress for official events this week, including walking behind the Queen’s coffin on Wednesday.

On Saturday evening, Harry was wearing the Blues and Royals, No.1 Uniform, KCVO Neck Order and Star, Afghanistan Operational Service Medal, Golden, Diamond and Platinum Jubilee medals and Army Pilot Wings.

William was wearing the Blues and Royals, No.1 Uniform, The Garter Sash, The Garter Star, Golden, Diamond and Platinum Jubilee medals and RAF Pilot Wings.

The brothers were joined in their silent tribute around the coffin by cousins Zara Tindall and Peter Phillips, Princesses Beatrice and Eugenie, and Lady Louise Windsor and her brother Viscount Severn.

The young royals, led by William, were in position at the top of the grand committee staircase in the corner of the vast hall at 5.58pm.

At 6pm, the tapping which signifies the changing of the guard sounded and William began walking down the steps, one at a time, followed by Harry, then Beatrice and Eugenie side by side, Louise and James side by side, and Zara and Peter also side by side.

Silence fell as members of the public looked on, with the only sound being the grandchildren’s footsteps on the stone.

William was positioned at one end of the coffin, facing the north entrance, while Harry was positioned at the opposite end, facing the area of the hall where thousands of people have entered over the last few days.

William stood with his hands clasped in front and his head bowed.

Louise and James’s parents, the Earl and Countess of Wessex, looked on from a platform facing the coffin.

Members of the public continued to file past while the Queen’s grandchildren stood guard, with some women wiping tears away from their face as they left the hall.

At 6.15pm, the tapping sounded and the grandchildren ended their vigil.

William led the group away from the coffin, followed by Zara and Peter, Louise and James, Beatrice and Eugenie, and finally Harry.

As the group made their way back up the corner staircase, Zara bent down to retrieve one of her shoes which appeared to have slipped off.

As the royals returned to their cars, Zara appeared to be linking arms with Harry, while Peter, Louise and Beatrice were walking along together.

On Friday evening, the Queen’s children – Charles, the Duke of York, the Princess Royal and the Earl of Wessex – took part in their own vigil.

They were all dressed in uniform, with an exception made for disgraced Andrew, who is no longer a working royal, to wear his military uniform as a “special mark of respect” for the Queen.