Richard Weight asks why prison policy is so difficult to unlock and whether anyone has the key. Crime is not getting any worse but the number of inmates has almost doubled in the last 20 years. What is more, the majority of prisoners reoffend, with an annual cost to the Treasury of more than 12 billion pounds. Featuring contributions from: Jonathan Aitken, former MP and prison inmate Professor Andrew Coyle, Professor of Prison Studies Baroness Corston, author of the Corston report on women's prisons Frances Crook, Director, Howard League for Penal Reform David Hanson MP, prisons minister Kenny MacAskill MSP, Scottish cabinet secretary for justice Ex-offenders from the Open Book Project, Goldsmith's College.