But for the glow from the campfire, it is impenetrably dark ... Api thought: This would be a good place for people, so he cracked the cave open. The first people to pull themselves out were ...

"Instead of being right on the water like they are today, these caves would have been near vast, open plains with large game animals like antelope," says Watson. "People hunted those animals ...

It was the middle of the 20th Century when England's last cave dwellers gave up their homes in a rural part of the country ...