A/74/136 B. Legal framework 88. Article 37 (b) of the Convention on the Rights of the Child provides that “no child shall be deprived of his or her liberty unlawfully or arbitrarily. The arrest, detention or imprisonment of a child shall be in conformity with the law and shall be used only as a measure of last resort and for the shortest appropriate period of time”. This establishes a high standard, applicable to all situations in which children are deprived of liberty. Together with the guiding principles of the Convention on the Rights of the Child, above all the best interests of the child, the prohibition of discrimination and the right of children to development and participation, this high standard requires States to reduce the detention of children to an absolute minimum by developing and applying appropriate non-custodial solutions. The precise extent to which the principle of measure of last resort allows deprivation of liberty depends on the type of detention. 89. States are required to develop specific child justice systems with the aim of diversion. If diversion measures are not possible, the principle of the shortest appropriate period of time needs to be applied, and so life imprisonment without possibility of release and other excessively long prison sentences should not be applicable. The Committee on the Rights of the Child, in its general comment No. 24 (2019) on children’s rights in child justice systems, states that, in the case of police custody, every child arrested should be brought before a competent authority to examine the legality of the deprivation of liberty or its continuation within 24 hours. In the case of pretrial detention it states that no child should be held longer than 30 days without formal charges being laid, and a final decision on the charges should be made within six months from the initial date of detention, failing which the child should be released. 90. In most States, primary caregivers, usually the mothers, who are sentenced to a prison term, are permitted to keep their young children with them in prison, if no other solution can be found, which satisfies the principle of the best interests of the child. In most States, children can stay with their caregivers until the age of three, but regulations differ considerably. It was found in the study that rigid State regulations are not effective, because they jeopardize a careful balancing of different interests on a case-by-case basis, and that the problem of children growing up in prisons can most easily be avoided if primary caregivers with young children are not sentenced to a prison term. 91. Detention for purely migration-related reasons is never in conformity with the Convention on the Rights of the Child. Whether children are on the move unaccompanied, separated or with their families, migration-related detention never meets the high standards of a measure of last resort in article 37 (b) of the Convention or of the best interests of the child in article 3 of the Convention, as there are always non-custodial solutions available, which need to be applied. 92. Similar considerations apply to children deprived of liberty in institutions. In principle, the United Nations, in its Guidelines for the Alternative Care of Children (General Assembly resolution 64/142) envisages that States should refrain from institutionalizing children who are in need of care, protection, education, rehabilitation or treatment. Where the immediate family is unable to care for a child with disabilities, article 23 (5) of the Convention on the Rights of Persons with Disabilities requires States to “undertake every effort to provide alternative care within the wider family, and, failing that, within the community in a family setting”. 93. States arrest and detain children associated with armed groups, be it because they have allegedly participated in hostilities during armed conflicts or 19-11838 17/23