This is HMP Weare in Portland Bill, Dorset. It was believed to be escape proof until a prisoner went 'over the wall' in 2003. It was closed in 2005 and then re opened a few months later after all the staf had gone and got new jobs, just in land is the main prison.
Google Earth Hacks is not affiliated with Google in any way
"Google" and "Google Earth" are trademarks of Google Inc.