MONITORING PLACES OF DETENTION : A PRACTICAL GUIDE 3. T HE O PTIONAL P ROTOCOL AGAINST TORTURE TO THE 44 UN C ONVENTION The Optional Protocol to the UN Convention against Torture (OPCAT) is based on the complementarity of visits to places of detention by international and national mechanisms: “The objective of the Protocol is to establish 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” (Art. 1 OPCAT). 3.1 The Sub-Committee to the CAT The Protocol foresees the creation of a Sub-Committee to the Committee against Torture (The Sub-Committee). This body will be composed of ten independent members, proposed and elected by the States Parties to the Protocol8, with relevant professional experience and representing the different regions and legal systems of the world. In its work the Sub-Committee should be guided by the principles of “confidentiality, impartiality, non-selectivity and objectivity” (Article 2). The mandate of the Sub-Committee is to visit places where persons are deprived of their liberty: it can have access not only to prisons or police stations but also, for example, to any centre for asylum seekers, to military camps, centres for juveniles, psychiatric hospitals and transit zones of international airports9. The Sub-Committee can only carry out “regular visits” and should establish a programme and inform the State parties. In addition, it can carry out a short follow-up visits to a regular visit. 8 9 This number will be increased to 25 after the 50th ratification. The type of place is the same as for national visiting mechanisms (see below).