Caves of the Mendip Hills traverse from one cave to another through the underground rivers led to the development of cave diving; the first cave dive attempt in Britain took place at Swildon's Hole in 1934. The first successful cave dive in Britain was achieved the following year at Wookey Hole Caves, where the last sump is currently the deepest in Britain at . The cave complexes at St. Dunstan's Well Catchment, Thrupe Lane Swallet, Lamb Leer and Priddy Caves have been identified as geological Site of Special Scientific Interest. There are also caves within the Cheddar Complex SSSI. A selection of the better known
Site of Special Scientific Interest things requiring planning permission (which are covered by the local planning authority consultation process). In Scotland, and following the implementation of the Nature Conservation (Scotland) Act 2004, Scottish Natural Heritage reviewed the ORC lists for each SSSI and removed those activities that were unlikely to happen and if they were to would be unlikely to damage the protected natural features, and other activities adequately regulated by other statutory regimes. The intention of this was to remove the need for owners and occupiers to obtain SSSI consent as well as licences/ permits from other authorities (who must consult SNH prior to