The European Committee for the Prevention of Torture and Inhuman or Degrading Treatment or Punishment, or CPT, defines solitary confinement as "whenever a prisoner is ordered to be held separately from other prisoners, for example, as a result of court decision, as a disciplinary sanction imposed within the prison system, as a preventive administrative measure or for the protection of the prisoner concerned". sec. 54; CPT Standards (2015) sec. 29. The CPT "considers that solitary confinement should only be imposed in exceptional circumstances, as a last resort and for the shortest possible time"..
