New research suggests that dozens of Bronze Age Britons were killed in an attack unlike any known to archaeologists studying this time period and location.

The study of human remains from Charterhouse Warren in southwest England, conducted by a team of researchers from multiple institutions, including the University of Oxford, was published in AntiquityJournal of World Archaeology. At least 37 Bronze Age men, women and children were found to have been "killed and butchered" and then cannibalised, with their bodies then thrown into a nearly 50ft deep natural shaft. Although archaeologists have found the remains of Britons from the Bronze Age and later who died violently, these incidents are largely isolated. Mass graves from this era have also been discovered, but the remains were laid respectfully, unlike those studied.

Researchers first became aware of the shaft in the 1970s. In the 1970s and 1980s, two excavations were carried out. Human remains, as well as some artifacts, including a flint dagger, were found at multiple locations in the shaft during these excavations. In total, more than 3,000 individual human bones and bone fragments have been found. These bones were used to estimate that at least 37 separate sets of remains were in the shaft. The varying lengths of the bones indicate that the people killed were male and female and ranged in age from infants to mature adults. Ongoing research is working to determine how people were related to each other.

The way the remains were destroyed made the detailed study possible, the researchers said. The trunk helped preserve the bones and kept them grouped together.

The bones "show clear evidence of blunt force trauma," according to the researchers, suggesting many of the people in the shaft "suffered a violent death." Other injuries, including scalp removal and severed jaw muscles, suggestive of removal of the tongue or lower jaw, also likely occurred, evidenced by bone scars, the researchers said. Some of the victims may have been decapitated or dismembered.

The victims may have been held captive or ambushed due to the severity of their injuries, the researchers said. It is unclear who could have carried out the attacks.

There is also evidence that the bodies were cannibalized, the researchers said, including human tooth marks on the bones and indicators that bone marrow, the soft tissue inside the bones, had been removed. The researchers said the cannibalism was likely carried out "in a context of violent conflict in which individuals were dehumanized and treated like animals".

"Approximately 37 men, women and children - and possibly many more - were killed at close range with blunt instruments and then systematically dismembered and deboned, their long bones broken in a manner that can only be described as butchery," the researchers said.

Later in the paper, the researchers refer to the scene as a "massacre" and suggest that it may even have been a "political statement" of violence so brazen that it would "reverberate in the wider region and over time." However, it is not clear what may have led to the violence: "Neither climate change, ethnic conflict, nor competition for material resources appear to offer convincing explanations," according to the researchers, leaving the only likely option that the violence erupted as part of a pattern of revenge or intercommunal violence.

"At this point, our investigation has raised as many questions as it has answered," the researchers said. "Work continues to shed more light on this decidedly dark episode of British prehistory."