Though it is called a camp on the map, it is actually an Iron Age boundary dyke or an unfinished hillfort, depending on who you listen to. From the aerial photo on multimap I must admit that the latter seems more likely. There is also evidence in the link posted by wideford that further justifies this conclusion (Evidence of post-holes for example)
I have seen it from the road, or from Caburn just to the east, for years, but never visited it. I plan to remedy that soon...