A/HRC/39/45 I. Introduction 1. The Working Group on Arbitrary Detention was established by the Commission on Human Rights in its resolution 1991/42. It was entrusted with the investigation of cases of alleged arbitrary deprivation of liberty, according to the standards set forth in the Universal Declaration of Human Rights and the relevant international instruments accepted by the States concerned. The mandate of the Working Group was clarified and extended by the Commission in its resolution 1997/50 to cover the issue of administrative custody of asylum seekers and immigrants. Pursuant to General Assembly resolution 60/251 and Human Rights Council decision 1/102, the Council assumed the mandate of the Commission. The mandate of the Working Group was most recently extended for a threeyear period in Council resolution 33/30 of 30 September 2016. 2. During the period from 1 January to 31 December 2017, the Working Group was composed of Sètondji Roland Jean-Baptiste Adjovi (Benin), José Antonio Guevara Bermúdez (Mexico), Seong-Phil Hong (Republic of Korea), Elina Steinerte (Latvia) and Leigh Toomey (Australia). 3. Mr. Adjovi served as Chair-Rapporteur of the Working Group from April 2016 to April 2017, and Mr. Guevara Bermúdez and Ms. Toomey as Vice-Chairs. At the seventyeighth session of the Working Group, in April 2017, Mr. Guevara Bermúdez was elected as Chair-Rapporteur and Ms. Steinerte and Ms. Toomey as Vice-Chairs. II. Activities of the Working Group in 2017 4. During the period from 1 January to 31 December 2017, the Working Group held its seventy-eighth, seventy-ninth and eightieth sessions. The Working Group also undertook two country visits to Argentina (8–18 May 2017) and Sri Lanka (4–15 December 2017) (see A/HRC/39/45/Add.1 and A/HRC/39/45/Add.2 respectively). 5. In order to facilitate outreach and information-sharing, the Working Group met with a group of non-governmental organizations in the context of its seventy-ninth session. 6. At its eightieth session, in November 2017, the Working Group adopted its revised deliberation No. 5 on deprivation of liberty of migrants, which is included in an annex to the present report. The document updates a deliberation issued in 1999 to tackle the situation of immigrants and asylum seekers held in prolonged custody without the possibility of administrative or judicial remedy. The new deliberation reflects changes in international law and the Working Group’s jurisprudence since then, as well as concern over the growing use of detention in the context of migration. A. 1. Handling of communications addressed to the Working Group during 2017 Communications transmitted to Governments 7. At its seventy-eighth, seventy-ninth and eightieth sessions, the Working Group adopted a total of 94 opinions concerning 225 persons in 48 countries (see the table below). 2. Opinions of the Working Group 8. Pursuant to its methods of work (A/HRC/36/38), in addressing its opinions to Governments, the Working Group drew their attention to Commission on Human Rights resolutions 1997/50 and 2003/31 and Human Rights Council resolutions 6/4, 24/7 and 33/30, by which those bodies requested them to take account of the Working Group’s opinions and, where necessary, to take appropriate steps to remedy the situation of persons arbitrarily deprived of their liberty and to inform the Working Group of the steps they have taken. At the expiry of a 48-hour deadline, the opinions were transmitted to the relevant sources. 3