International legal instruments relating to pre-trial justice and the prevetention of torture
The most important international human rights instruments relevant to pre-trial detention are the Universal Declaration of Human Rights and the United Nations Convention against Torture and Other Cruel, Inhuman or Degrading Treatment and Punishment (Convention Against Torture) and its associated Optional Protocol (OPCAT).
In terms of the Convention Against Torture all States parties are obliged to submit regular report to the Committee Against Torture initially one year after acceding to the Convention and then every four years. The Committee examines each report and addresses its concerns and recommendations to the State party in the form of "concluding observations".
The Optional Protocol to the Convention against Torture and other Cruel, Inhuman or Degrading Treatment or Punishment (OPCAT) provides for the establishment of "a system of regular visits undertaken by independent international and national bodies to places where people are deprived of their liberty, in order to prevent torture and other cruel, inhuman or degrading treatment or punishment" to be overseen by a Subcommittee on Prevention of Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment.
Under the OPCAT, the Subcommittee on the Prevention of Torture (SPT) has unrestricted access to all places of detention, their installations and facilities and to all relevant information. The SPT visits police stations, prisons (military and civilian), detention centres (e.g. pre-trial detention centres, immigration detention centres, juvenile justice establishments, etc.), mental health and social care institutions and any other places where people are or may be deprived of their liberty.
The UN also appoints a Special Rapporteur on Torture to examine questions relevant to torture, whose mandate covers all countries, irrespective of whether a State has ratified the Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment.