The Queen’s grandchildren will stand guard around her coffin in London on Saturday, hours after their parents held an emotional vigil in the Palace of Westminster.

Notably, the Duke of Sussex will join his brother the Prince of Wales in wearing uniform in Westminster Hall, ahead of the Queen’s state funeral on Monday.

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 say the King has decided his youngest son can wear uniform for the vigil, saying he will stand at the foot of the coffin, with William at the head.

Despite being a former Army officer, Harry has been in civilian dress for official events, including walking behind his grandmother’s coffin on Wednesday when it was carried to Westminster Hall for lying in state.

William will be flanked by his cousins Zara Tindall and Peter Philips, while Harry will be with Princesses Beatrice and Eugenie, with Lady Louise Windsor and her brother Viscount Severn at the middle of the coffin.

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.

The King, Anne, Andrew and Edward had solemn looks on their faces as they stood vigil around their mother’s coffin, with their heads bowed throughout as members of the public filed slowly past them.

It comes as final preparations are under way for the funeral on Monday, with politicians and royal dignitaries from around the world expected to arrive throughout the weekend.

On Saturday, Prime Minster Liz Truss will meet the prime ministers of Australia and New Zealand – Anthony Albanese and Jacinda Ardern – at the Government’s Chevening country residence, a No 10 spokesperson said.

Charles will also meet chiefs of staff at Buckingham Palace on Saturday and visit police headquarters to thank the emergency services for their work in planning the funeral.

On Sunday, Ms Truss will meet Irish Taoiseach Micheal Martin, Canadian premier Justin Trudeau, Polish President Andrzej Duda and US President Joe Biden at Downing Street.

She will have an audience with the King before attending his reception for visiting heads of state at Buckingham Palace on Sunday.

Charles concluded his tour of the home nations on Friday, starting his day with a visit to Wales, after trips to Northern Ireland and Scotland in recent days.

Meanwhile, thousands of people continue to queue to see the Queen’s coffin lying in state, with some facing more than a day in line.

Early on Saturday morning, the Department for Digital, Culture, Media & Sport’s queue tracker warned people not to travel to join the back of the queue, but it changed the guidance at 8am saying the line had reached Southwark Park with wait times “at least 24 hours”.

Those inside Westminster Hall were briefly shocked on Friday night when a man was arrested after moving out of the queue to approach the Queen’s coffin.

Metropolitan Police said the incident occurred around 10pm, as the live feed from inside the hall cut away for a brief period.

A statement from Scotland Yard said: “Around 22:00hrs on Friday 16 September officers from the Met’s Parliamentary and Diplomatic Protection Command detained a man in Westminster Hall following a disturbance.

“He was arrested for an offence under the Public Order Act and is currently in custody.”

Two thousand people will gather inside Westminster Abbey in London on Monday for the Queen’s funeral.

Some 800 people, including members of the Queen’s Household and Windsor estate staff, will attend the committal service afterwards at 4pm in St George’s Chapel, Windsor Castle.

After the funeral, the King and members of the royal family will walk behind the Queen’s coffin to Wellington Arch when it leaves Westminster Abbey, before it is driven to Windsor on the state hearse.