In the picture, the soldier appeared to be supported by the policeman while lying down on the stretcher.
On Saturday afternoon, London temperatures were relatively lower than those experienced over the past few days.
Nevertheless, the 22C being felt in central London may have taken a toll on the soldier, particularly when paired with the stress of the day.
This isn’t the first time a similar incident has happened.
Just last weekend, as Prince William was reviewing the troops at London’s Horse Guards Parade ahead of the event, at least three guardsmen fainted.
The Prince of Wales, who carried out the duty as the honorary colonel of the Welsh guards, issued a statement later acknowledging the “difficult conditions” in which the soldiers undertook the last rehearsal before Trooping the Colour.
Taking to Twitter, the heir to the throne said: “A big thank you to every soldier who took part in the Colonel’s Review this morning in the heat. Difficult conditions but you all did a really good job.”
Members of the Welsh guards wear real bearskin hats sourced from Canadian pelts, first introduced after the Battle of Waterloo in 1815 with the aim to make soldiers appear taller and more intimidating to the enemy, according to BBC Wildlife.
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The hat isn’t just considerably long, as the standard bearskin cap of the Foot Guards measures 18 inches, but it’s also rather heavy when considering it is to be worn for several hours, weighing 1.5 pounds.
Also soldiers not donning the Welsh Guards’ uniform are known to have collapsed during official events in the past.
One was caught on camera crashing to the floor on the day of the Coronation of King Charles last month.
The unfortunate soldier was taking part in an event at Cardiff Castle in Wales along with the 104 Regiment Royal Artillery.
Another, a flagbearer, also fainted in London while taking part in the Coronation Procession.
The fainted soldier was among the 1400 parading troops, 200 horses and 400 musicians who came together today in a major display of military precision, horsemanship and pageantry to celebrate the first official birthday of the newly-crowned King.