Panorama footage in one of Britain's biggest jails exposes widespread drug use and a lack of control.
Undercover reporter Joe Fenton tells his story of working in the crisis-hit prison system.
Former deputy prime minister Nick Clegg calls for a big cut in the prison population of England and Wales.
Ed Thomas finds violence and drugs are rife, and staff are overstretched
David Aaronovitch explores the political background to prison policy.