One optional protocol – the Optional Protocol to the Convention against Torture (OPCAT) – establishes an additional treaty body in order to undertake a regime of visits to places of detention or places where persons may otherwise be deprived of their liberty. This treaty body is called the Sub-Committee on Prevention of Torture (SPT) and it consists of 25 independent experts elected by States parties to OPCAT. It cooperates with national mechanisms for the prevention of torture established in each State party. ICESCR assigns responsibility for monitoring implementation of the Covenant to the Economic and Social Council which has chosen to create a committee of independent experts – the Committee on Economic Social and Cultural Rights (CESCR) – to assume its monitoring functions. CESCR is modelled on the other treaty bodies but differs from them in two important regards: it is not formally a treaty body since it owes its existence to a resolution of ECOSOC rather than the Covenant and its members are elected by the members of ECOSOC rather than States Parties. Nevertheless, the Committee is generally considered to be one of the human rights treaty bodies. What is the relationship between the treaty bodies and the United Nations? Although the treaty bodies are not formally United Nations bodies established under the Charter, they are considered an integral part of the United Nations human rights system. The treaties themselves were adopted by the General Assembly; however, their legal force comes from their acceptance as legally-binding multilateral treaties by their States parties. The provisions of the treaties nevertheless envisage a close relationship between the treaty bodies and the United Nations. In practical terms, the relationship between the treaty bodies and the United Nations is formalized in three important and related aspects: (1) the treaties provide for the treaty bodies to meet at United Nations Headquarters in New York or Geneva 05