An examination of current and future prison designs, within the government's building programme and the confines of penal philosophies and legislation. America has led the way in prison design, with two main types of architecture predominating: radical layouts (outside cells with windows) and linear blocks (inside cells with grilles). Now new generation prisons (central association surrounded by small groups of cells) look set to become the fashion. But are they a better answer, and should they be copied worldwide before we know?