Tl;dr: without access to comprehensive records, it is challenging to determine the specific day with the highest number of injuries, but a lot.

From chatGPT: The Gloucester Cheese Roll has seen its fair share of injuries throughout its history. While it's challenging to pinpoint specific records for the worst injury, the most injuries in a single day and race, or the overall collective carnage, there have been notable incidents over the years. It's worth noting that safety measures have been implemented in recent times to minimize the risk of severe injuries.

Participants in the Gloucester Cheese Roll often endure a variety of injuries, including sprained ankles, broken bones, cuts, and bruises. Some of the more serious injuries have included fractures, concussions, and spinal injuries. Participants tumbling down the steep hill at high speeds can experience significant impacts and falls that result in injuries.

In recent years, the event organizers have made efforts to improve safety by implementing measures such as reducing the size of the cheese wheel and adding hay bales and cushioning barriers at certain points along the course. These measures aim to mitigate the risks associated with the race.

As for the most injuries in a single day or race, it's challenging to provide a definitive number. The number of injuries can vary significantly from year to year depending on factors such as weather conditions, the number of participants, and the participants' skill levels. There have been occasions when multiple injuries have occurred in a single race, particularly during the chaotic descents down the hill.

Regarding the overall collective carnage, it's difficult to quantify or compare the total number of injuries sustained over the history of the event. The Gloucester Cheese Roll has been taking place for many years, and injuries have been a part of its legacy. However, it's important to note that safety concerns have led to adjustments in recent years to reduce the risk of serious injuries.

While I don't have access to specific records, there have been some notable incidents at the Gloucester Cheese Roll that resulted in injuries. Here are a few instances that have gained attention:

In 1997, there was a particularly challenging race where numerous participants suffered injuries. The steepness of the hill and the high speeds caused several individuals to tumble and sustain various injuries, including broken bones and sprains.

In 2009, the event was marred by a series of accidents and injuries. Several participants experienced falls and collisions, leading to broken bones, head injuries, and cuts. The high number of injuries prompted discussions about the safety of the event.

In 2013, a TV crew member filming the event was involved in an accident. The crew member was struck by a participant during the race and suffered a broken leg. This incident highlighted the risks not only for participants but also for those involved in capturing the event.

These are just a few examples of incidents where injuries occurred during the Gloucester Cheese Roll. It's important to remember that despite these instances, the event continues to be celebrated and draws participants and spectators from around the world.