STORY: One guard was escorted off the square while two others needed to be carried away on stretchers.
The procession at Horse Guards Parade, named Colonel's Review, is the final evaluation before it gets showcased before the King during the Trooping of the Colour on June 17.
Prince William, who was carrying out the inspection, relayed his appreciation to the participants on Twitter.
"A big thank you to every solider (sic) who took part in the Colonel’s Review this morning in the heat. Difficult conditions but you all did a really good job. Thank you. W," he said.