A/74/136 empower them to foster the physical, mental, spiritual, moral and social development of their children, including children with disabilities. 100. In all decisions that may lead to the detention of children, the Independent Expert calls upon States to most rigorously apply the requirement of article 37 (b) of the Convention on the Rights of the Child that deprivation of liberty shall be applied only as a measure of last resort in exceptional cases, and that the views of children shall be heard and taken duly into account. 101. The Independent Expert calls upon States to repeal all laws and policies that permit the deprivation of liberty of children on the basis of an actual, or perceived, impairment. 102. If detention is unavoidable under the particular circumstances of a case, it shall be applied only for the shortest appropriate period of time. States have an obligation to apply child-friendly conditions, without any discrimination. Children shall not be exposed to neglect, violence, sexual abuse or exploitation, ill-treatment, torture and inhuman conditions of detention. States should ensure that children have access to essential services aimed at their rehabilitation and reintegration into society, including education, vocational training, family contacts, sports and recreation, adequate nutrition, housing and health care. Health services in detention shall be of a standard equivalent to that available in the community at large. 103. Since children have the right under article 12 of the Convention on the Rights of the Child to actively participate in all matters directly affecting their lives, they shall be empowered to influence decisions relating to their treatment and enjoyment of such essential services and have the right to effective remedies, as well as to lodge complaints to an independent and impartial authority on any grievances and human rights violations during detention. Furthermore, States are strongly encouraged to ratify the third Optional Protocol to the Convention on the Rights of the Child on a communications procedure, enabling children to further seek redress for violations of their rights. 104. States are strongly encouraged to ratify the Optional Protocol to the Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment and to establish independent and effective national preventive mechanisms with a particular expertise, to conduct visits to places where children are, or may be, deprived of liberty. 105. States should enhance the capacity, by means of investing in human resources, awareness-raising and systematic education and training, of all professionals who work with and for children in decisions leading to their deprivation of liberty, and those who are responsible for their well-being while in detention. This applies to the police, judges, prosecutors, prison guards, psychiatrists, medical personnel, psychologists, educators, probation officers, social workers, child protection and welfare officers, asylum and migration personnel and any other individuals in contact with children at risk of deprivation, or deprived, of liberty. 106. States are strongly encouraged to establish an appropriate system of data collection at the national level, involving all relevant ministries and other State agencies, coordinated by a focal point. Whenever possible, data on children should be obtained directly from them in accordance with the principle of informed consent and self-identification. When necessary, such information should be supplemented by data concerning their parents or primary caregivers. 19-11838 19/23