EXECUTIVE SUMMARY This handbook aims at supporting the among detainees whom they are most work of national preventive mechanisms likely to affect. (NPM) in the European Union (EU) in monitoring the rights of persons and groups in a situation of vulnerability. As the European Court of Human Rights (ECtHR) has held in a number of judgments, prisoners, just as any person Article 1 of the Optional Protocol to the in the custody of the state, are persons Convention against Torture and other in Cruel, Inhuman or Degrading Treatment authorities are under a duty to protect or Punishment (OPCAT), the treaty on them. There are however also among the basis of which the NPMs function, prisoners groups in a situation of specific provides for the establishment of a vulnerability. The existing international system of regular visits undertaken by standards independent international and national inter alia women, children, foreigners, bodies to places where people are deprived persons with disabilities, lesbian, gay, of their liberty, in order to prevent torture bisexual, and other cruel, inhuman or degrading queer persons (LGBTIQ), ethnic and treatment or punishment. The effective racial minorities and indigenous peoples. prevention of such practices presupposes As a rule, the situation of vulnerable targeting them through visits to places groups in prison, including the specific where they are most likely to occur, and groups, the attitudes towards persons a vulnerable have situation, recognized transgender, and as intersex the such and