A/HRC/35/25/Add.1 of non-refoulement is being eroded, considering the sharp increase in immigration arrests of migrants and refugees, and the difficulties they experience in gaining access, once detained, to legal representation, civil society organizations or international organizations. The Special Rapporteur urges the Government to implement oversight mechanisms that will allow it to ensure the fulfilment of the principle of non-refoulement. E. Bilateral agreements 54. The Special Rapporteur commends Angola for having joined the Community of Portuguese-speaking Countries and can see the benefits of advancing in that Community. The Special Rapporteur observes that it is important to have additional arrangements that ensure that the preference for “highly skilled” labour is not implemented to the detriment of the human rights of “low-wage” migrant workers. V. Detention 55. Migrants are arrested under suspicion of irregular entry or stay, often in spite of the documents presented, and, if necessary, taken to a detention centre while their documents are verified or arrangements relative to their expulsion are being finalized. 56. Mandatory detention of undocumented migrants and asylum seekers is neither a legitimate nor an effective tool for deterring undocumented migration and instead has the opposite effect of driving them further underground. 57. The Special Rapporteur expresses his regret that, on the day that he visited the detention centre in Cabinda, there were no migrants present and he was therefore unable to make a proper assessment of how the detention centre works. The Special Rapporteur was informed by government officials that migrants are kept there for only up to 12 hours. In the Trinta detention centre, the Special Rapporteur met with only five detainees, when the capacity is of over 500. He was informed that many migrant detainees had been released prior to his visit. 58. The Special Rapporteur was informed that arrested migrants may be subjected to harsh, overcrowded and unsanitary detention conditions. There is little access to basic hygiene products such as soap or sanitary napkins. Detainees have little privacy and seem to be allowed access to telephones only in order to obtain bribery money from family and friends. Crucially, they do not have access to justice. They receive little legal information, have difficulty accessing lawyers and have no access to legal aid. Detention is indefinite and ends only upon the expulsion of the undocumented migrant, the verification of documentation, which is a lengthy process, or release after payment of a bribe. 59. In the Trinta detention centre, detainees are kept in large groups in different rooms, one of which is allocated for women only. Movement out of the rooms is restricted to meal times. Young children are kept with their mother and older male children are kept with the men. Additionally, detainees suffer from harassment, degrading treatment and physical violence and lawyers trying to defend migrants are occasionally intimidated. 60. The detention of migrants is not subject to independent monitoring and takes place without prior authorization from a judicial body. Investigations conducted by the Attorney General to review the legality of detention are usually extremely lengthy. Furthermore, detainees are sometimes denied contact with the outside world, including legal assistance. 61. The Special Rapporteur received information that children are being detained. As stated by the Committee on the Rights of the Child, children should always be treated as children first and foremost, and the principle of the best interests of the child should always guide all decisions regarding children, whatever their administrative status and circumstances. Detention can never be in the best interest of a child and children should never be detained for reasons relating to their migratory status or that of their parents. Children and families with children should always benefit from alternatives to detention. 12