A/HRC/8/3 page 27 international standards that should guide the use of these tools and underlying factors that must be addressed to enable progress. 76. The Government’s legal power to determine which prisoners are confined to which cells, wings and prisons at which times provides one powerful example of the tools Governments have to retake control from prisoner authorities and prevent prisoner-on-prisoner violence. The power to control inmates’ movements can be used to disrupt particular circumstances in which inmates attempt to become prisoner authorities, dominating and coercing fellow prisoners. Particularly vulnerable individuals, including ones who have been threatened by other prisoners, may be given protective custody. Prisoner authorities may themselves be moved and isolated from the rest of the prison population.92 77. In addition to these separation measures, staff can systematically classify and segregate new inmates in such a way as to reduce the opportunities and incentives for inmates to form violent organizations. International human rights treaties require that some groups of inmates be separated, providing that accused persons shall be segregated from convicted persons,93 juvenile offenders shall be segregated from adults94 and migrant workers held for migration-related violations shall be segregated from convicted persons or persons awaiting trial.95 Other criteria for segregation are enumerated in standards instruments adopted by international bodies. These include the separation of men from women and of persons detained for civil offences from those detained for criminal offences.96 International standards also suggest the importance of classification to encourage rehabilitation and discourage recidivism.97 78. These broad categories, however, provide only a starting point for national authorities. While Governments must avoid classifications that would be inconsistent with human rights law prohibitions on discrimination, there are numerous other country-specific criteria that may be relevant, including gang affiliation (whether as a criterion for grouping or separating), past behaviour in prison and the severity and character of the offence committed. To make any such effort effective, it must be approached systematically. First, the Government should develop a 92 Note, however, that sustained and comprehensive isolation can violate human rights law requirements that “persons deprived of their liberty shall be treated with humanity and with respect for the inherent dignity of the human person” and that “[n]o one shall be subjected to torture or to cruel, inhuman or degrading treatment or punishment” (ICCPR, arts. 7, 10 (1). The “super max” approach of continuous single cell confinement for the worst perpetrators has, in particular, raised serious concerns. 93 ICCPR, art. 10. 94 ICCPR, art. 10; Convention on the Rights of the Child, art. 37. 95 International Convention on the Protection of the Rights of All Migrant Workers and Members of Their Families, art. 17. 96 97 Standard Minimum Rules, art. 8. Standard Minimum Rules, arts. 67-69; United Nations Rules for the Protection of Juveniles Deprived of their Liberty, arts. 27-29.