Contributor(s): Professor Jill Peay, Anita Dockley, Dr Tim Exworthy | Prisons are populated by offenders with various forms of mental disorder. How does the law justify this, does their presence undermine the legitimate purposes of imprisonment, and should anything be done? Jill Peay is professor of law at LSE. Anita Dockley is research director for the Howard League for Penal Reform. Tim Exworthy is clinical director and consultant forensic psychiatrist at St Andrew’s Hospital.