A number of guardsmen fainted during the heat at the Queen's Trooping the Colour ceremony.
As the royal family looked on, one of the soldiers was captured on camera falling during the performance at Horse Guards Parade.
After taking the tumble, two officials were dispatched to collect the soldier, a member of the Household Division, which was inspected by Her Majesty.
The 1,000 of serviceman on parade maintained their positions as if nothing had happened during the incident.
In all, five Guardsman were stretchered off over the course of the ceremony as temperatures in London today hit 29C.
An Army spokesperson told the International Business Times: "We can confirm that during the Queen's birthday parade today a small number of soldiers fainted.
The Trooping the Colour ceremony at Horse Guards Parade. (Credit: PA Images)
"It is an extremely hot day and all were removed from the Parade and checked by medical staff where they were hydrated."
The ceremony has been a tradition of British infantry regiments since the 17th century, although the roots go back much earlier, and today marks the Queen's official 91st birthday.
Despite the pomp and pageantry, the Queen used the occasion to reflect on the number of recent national tragedies, including the Grenfell Tower blaze in which 70 people remain unaccounted for and 30 have been officially confirmed dead, with the death toll expected to rise.
Members of Britain's Royal family look out from the balcony during the ceremony. (Credit: PA Images)
The Queen said in her message: "Today is traditionally a day of celebration. This year, however, it is difficult to escape a very sombre national mood. In recent months, the country has witnessed a succession of terrible tragedies.
"As a nation, we continue to reflect and pray for all those who have been directly affected by these events."
Queen Elizabeth II meets firefighters during a visit to Kensington where the Grenfell fire took place. (Credit: PA)
Before the Queen arrived at today's ceremony, relatives of the men on the parade ground observed a minute's silence for the victims of the fire.
Yesterday, Prince William and the Queen met firefighters during a visit to the Westway Sports Centre, which is providing temporary shelter for those who have been made homeless by the blaze.
Featured Image Credit: PA