A/HRC/35/25 (j) Collection and analysis of disaggregated data on all aspects of border management, including return of migrants. Goal 4. End the use of detention as a border management and deterrence tool against migrants Rationale 58. It is a worrying trend that immigration detention is extensively used as a border management and deterrence tool against migrants and too often as a means to prevent their access to justice. In line with international human rights law, freedom must be the default position and detention the exception, used only as a measure of last resort. Detention must be reasonable, necessary, proportionate, decided on a case-by-case basis and enforced for the shortest possible period of time. Administrative detention can be justified only if an individual presents a danger to the public or risks absconding when their presence is necessary in further proceedings, and such determinations must be made individually and on the basis of evidence. Furthermore, when detention becomes a routine measure of border enforcement, it may be, per se, arbitrary insofar as it is neither an exceptional measure of last resort, nor based upon a meaningful individualized assessment of risk. 59. The increasing practice of migration detention is not automatically accompanied by assurances of legal guarantees and basic human rights protection for detainees. The access of migrants to justice is severely hampered by a failure to guarantee appropriate detention safeguards for vulnerable individuals and access to proper legal representation, legal aid, consular services, interpretation and translation services and effective remedies. 60. The impact of prolonged detention, coupled with the frequently inhuman detention conditions (namely, overcrowding, unsanitary personal hygiene facilities and kitchens and insufficient access to health care, family members, lawyers, international or civil society organizations and physical and recreational activities), has a devastating effect on the physical and mental health of migrants. Long periods of immigration detention can also lead to sustained barriers to the ability of migrants to claim their economic and social rights, even after having been released. 61. Unaccompanied migrant children and families with children must never be detained for reasons relating to their administrative immigration status. The detention of children, even for short periods, can have severe psychological consequences for their development. The Committee on the Rights of the Child and other human rights mechanisms have made it clear that immigration detention can never, ever, be in the best interest of a child and that the immigration detention of children, whether unaccompanied or with their families, always constitutes a violation of their rights. Consequently, both unaccompanied migrant children and families with children should always be provided with alternatives to detention. 62. Many rights-based alternatives to detention exist, including registration requirements, the deposit of documents, the payment of bonds or bail or the provision of a surety or guarantor, reporting requirements, case management or supervised release, designated residence, electronic monitoring and home curfew or house arrest. A number of countries have moved towards open reception facilities, in particular for vulnerable migrants such as unaccompanied minors and families. However, prolonged immigration detention and its associated negative human rights consequences continue in many countries. Targets 16 4.1. Clearly define and exhaustively enumerate the reasons for immigration detention in legislation, in accordance with international human rights law 4.2. Ensure that the detention of migrants is always a measure of last resort, permissible only when reasonable, necessary, proportionate, decided on a case-by-case basis and enforced for the shortest possible period of time