This is a bit misleading, because Cardiff City Council doesn't actually own it, it merely has a lease of it, up until 2074. The owner is the Crown Estate. I expect the Crown Estate would control what you can actually do with it, for example the fact taht it is a Local Nature Reserve is a condition of lease. It is also an SSSI. It has a guesthouse, an operating lighthouse and foghorn, and a number of ruined buildings. There is also some infrastructure associated with a sustainable energy demonstration project.