Cave hidden beneath Welsh castle could rewrite Britain’s prehistoric story

A major new archaeological project is set to investigate a vast cave hidden beneath a Welsh castle, where early excavations have already uncovered some of the most significant prehistoric finds in Britain.

The five-year project will focus on Wogan Cavern beneath Pembroke Castle, following new funding from the Calleva Foundation awarded to the University of Aberdeen.

Researchers say the site has the potential to transform understanding of prehistoric life in Britain, after initial work revealed evidence of human and animal activity spanning more than 100,000 years.

Wogan Cavern, which is accessed via a spiral staircase from within the castle, was long believed to have been heavily disturbed during Victorian excavations. As a result, archaeologists assumed little material of significance remained.

However, small-scale digs carried out between 2021 and 2024 told a very different story. Excavations uncovered well-preserved sediments containing animal bones, stone tools and evidence of repeated human occupation across multiple prehistoric periods.

Finds from the site include remains of mammoth, woolly rhinoceros, reindeer and wild horse, alongside more unusual discoveries such as hippopotamus bones dating back around 120,000 years, when warmer conditions allowed such species to roam what is now Wales.

The new project will be led by Dr Rob Dinnis of the University of Aberdeen, who directed the earlier excavations.

He said the cave was already proving to be one of the most important prehistoric sites discovered in Britain.

“Despite the limited work done so far, we can already say that Wogan Cavern is a truly remarkable site,” he said.

“Not only is there extremely rare evidence for early Homo sapiens, there are also hints at even earlier human occupation, probably by Neanderthals.

“There is no other site like it in Britain – it is a once-in-a-lifetime discovery.”

The expanded excavation will allow archaeologists to build a clearer picture of how the cave was used over tens of thousands of years, including by early modern humans and potentially Neanderthals.

Researchers hope the site will provide insights into how prehistoric people adapted to dramatic environmental changes, from the last Ice Age to earlier warmer periods.

Dr Dinnis added: “We are optimistic that the cave can chart a long sequence of human activity, from hunter-gatherers living there immediately after the last Ice Age around 11,500 years ago, back to Britain’s earliest Homo sapiens between 45,000 and 35,000 years ago.”

DNA analysis

The project will draw on a range of advanced scientific techniques, including high-resolution dating and analysis of ancient DNA preserved in both bones and cave sediments.

Professor Kate Britton, a specialist in archaeological science at the University of Aberdeen, said the condition of the material offered rare opportunities for detailed study.

“Because the bones are well preserved, we can learn a lot about past environments and ecosystems, and do high-resolution scientific dating,” she said.

“Pilot studies have shown that ancient DNA is preserved, in both the bones and the cave sediments.”

The work is being supported by the Pembroke Castle Trust, which plans to expand its team and facilities to ensure discoveries from the cavern are curated locally.

‘Huge significance’ 

Dr Jonquil Mogg, collections manager at Pembroke Castle, said the discoveries could add a new dimension to the site’s historical importance.

“Pembroke Castle has long been a very important part of Welsh and British history,” she said. “Wogan Cavern has the potential to also establish it as a place of huge significance to British archaeology.”

Castle manager Jon Williams said the findings had already generated excitement.

“We have watched with great interest as Wogan Cavern has started to reveal its secrets – it’s very different from the medieval history we usually deal with at the castle,” he said.

“We are thrilled that work on this wonderful cave will continue and look forward to securing the collection for the people of Pembroke, Wales and beyond.”

The next phase of excavations is due to begin at the end of May.