Re:On what basis? (Score 1)

Based on what? Copyright applies to specific words on a page, not the ideas behind those words. Ever hear of the Munsters? Ever wondered why the producers didn't get sued into oblivion by the producers of the Addams Family? Because there is no case in copyright law. There is no room for manouver here.

I don't know about this Harry Potter case, but there is different unrelated law concerning "passing off" - e.g. calling your trainers Hikes or Reebox, or calling your book Henry Potter. Nothing to do with copyright.