Long Tor Grotto
No known access restrictions. Limited off-road parking. Entrance passage is half full of deep black smelly mud from road run-off, and almost certainly contains sewage.
Beware of bad air, a deep flooded hole in floor 16m into entrance passage on left, and risk of Weil's disease from rats associated with sewage seepage. Wear waders if possible for entrance passage as mud is deeper than wellies and disgusting.