Mendip Hills to the development of cave diving in Britain. The first cave dive was attempted at Swildon's Hole in 1934, and the first successful dive was achieved the following year at Wookey Hole Caves, which has the deepest sump in Britain at 76 m (250 ft). The cave complexes at St. Dunstan's Well Catchment, Lamb Leer, and Priddy Caves have been identified as Sites of Special Scientific Interest. The deepest cave in the Mendip Hills is Charterhouse Cave with a vertical range of . Many caves in the Mendip area were excavated for archaeological and natural history studies by pioneer explorer
Wookey Hole Caves SSSI designation, which would restrict what farmers and other landowners were allowed to do, would cover the entire catchment area. This was opposed as being too restrictive and difficult to enforce. It was argued that agricultural uses of fields which were not directly in contact with cave entrances would have little detrimental effect on the caves themselves. There was also debate about which caves and cave features should be considered "important". The final settlement resulted in a smaller area being designated and many agricultural practices being removed from the list of proscribed "Potentially Damaging Operations". The entrance weir and sluice