A guard passed out from the stage while standing guard next to the Queen’s Coffin as she lay in state at the Palace of Westminster.
Hundreds of thousands of mourners have lined up to pay their last respects to the monarch after her death in Balmoral on Thursday.
But onlookers were stunned when a guard began to rock on his feet just before he collapsed.
The man had briefly stepped off the stage moments earlier before taking his place again as other soldiers joined him for a switchover.
But seconds later, he blacked out and fell forward, landing sprawled on the stone floor to the loud sobbing of bystanders queuing to pay their respects.
The live stream also went out for a few minutes when the police came to the aid of the man.
The Queen’s casket, which is placed on a raised platform called a catafalque, is guarded around the clock by units of the Sovereign’s Bodyguard, the Household Division of Yeoman Warders of the Tower of London.
The moment the guard fell forward on the stone floor while police officers quickly come to his rescue tonight
Members of the audience in the historic hall to pay their last respects gave loud claps as the man fell
Two police officers rushed to help the man while the remaining guards stood guard next to the coffin
It comes after crowds lined the streets of central London when she was moved from Buckingham Palace to Westminster Hall on Wednesday afternoon.
King Charles, William and Harry gathered to mourn and march behind the coffin making its final journey from Buckingham Palace at 2:22 p.m.
A short service involving the Royal Family was held at the Palace of Westminster, before the public was allowed access from 5pm to pay their respects.
When the late monarch’s coffin was placed in the entrance hall, photos captured a poignant moment for the Duke of Sussex as he held his head in one hand, shielded his eyes and looked down.
Dressed in a medal-adorned suit, he stands next to the Duchess of Sussex, who looks down with a somber expression on her face.
Prince Harry and his brother Prince William stood with their wives Meghan and Kate as they put aside their bitter feud to pay their respects to their grandmother.
As the siblings walked side by side for the harrowing 38-minute procession from Buckingham Palace, their spouses traveled in separate cars, with Meghan accompanied by the Countess of Wessex and Kate accompanied by Camilla, the Queen Consort.
During the service, the ‘Fab Four’ stood in formation facing the coffin on its purple-covered catafalque, which was flanked by a tall, yellow flickering candle at each corner of the broad scarlet platform at the heart of Westminster Hall – the backdrop of some of the most famous moments in British history.
Just as the first members of the public walked into the Palace of Westminster to see the Queen’s coffin as it lay in state until Monday
Members of the public pay their respects as they pass by Queen Elizabeth II’s coffin at the Palace of Westminster tonight
People queue as Britain’s Queen Elizabeth’s casket arrives at Westminster Hall from Buckingham Palace laid out for her
The Sussexes were in the back of the group of royals, with Harry directly behind William and Meghan behind Kate. The touching moment marks the couple’s first time together since their surprise walk together at Windsor Castle on Saturday, and a rare show of togetherness.
The Queen’s casket entered Westminster Hall as the choir of Westminster Abbey and the choir of His Majesty’s Chapel Royal, St James’s Palace, sang Psalm 139. When the Queen arrived, Charles, William and Anne saluted. Harry and Prince Andrew – who were not allowed to wear military uniforms – bowed their heads instead.
Thousands of well-wishers have gathered through the historic hall all evening and into the early hours.
Mourners waiting to pay their respects have been given color-coded wristbands to temporarily leave the line to buy food and go to the bathroom.
Stewards manning the route have also been advised to take people who might be having a hard time spotting them from the line for a ‘cup of tea’. They may then be admitted closer to the front.
The Palace of Westminster remains open 24 hours a day until 6.30am on Monday – the day of the Queen’s funeral.