NTD's Lee Hall sits down with former prisoner and prison reform advocate David Shipley for a unique insight into the criminal justice system.
David talks about the overcrowding of prisons, pressure on the probation service and the problems of reoffending. He discusses the horrifying things he experienced when locked up that made him want to dedicate himself to improving the prison system.
He also shares how some of the closest bonds of friendship are formed by people incarcerated together.