A/HRC/13/30 trial guarantees as contained in article 10 of the Universal Declaration of Human Rights and articles 9 (3) and 14 of the International Covenant on Civil and Political Rights. However, given the gravity of the violation of fair trial guarantees, which is a condition for the Working Group to declare the detention to be arbitrary, and the time that the individual concerned has already spent in (pretrial) detention, conditional release, release on bail, or other forms of release pending trial would also typically be the appropriate remedy. 85. In its Opinions, the Working Group encourages States which have not ratified the International Covenant on Civil and Political Rights to do so. When it may wish to restate or develop its jurisprudence on a matter of importance or on a point of law, or call on the States to amend their national legislation or to change their practices to bring them into conformity with its international human rights obligations, it may, under exceptional circumstances, render an Opinion even though the person has been released. In any given case, the Working Group may remind States of their obligation in terms of article 9 (5) of the International Covenant on Civil and Political Rights to provide compensation to the released person. 86. The Working Group has begun to make more frequent and express references to its own jurisprudence, and to that of international, regional and national human rights bodies and courts. Conversely, the Working Group welcomes the fact that the findings and recommendations, contained in its reports and Opinions are increasingly made use of by other United Nations human rights bodies and national and regional human rights courts. When national courts are determining the extent of international law obligations which often have a direct or indirect effect on matters before them, the reports and Opinions of the Working Group may also be of assistance. IV. Conclusions 87. The Working Group, in the fulfilment of its mandate, welcomes the cooperation it has received from States concerning cases brought to their attention. 88. The Working Group considers that country and follow-up visits are of the utmost importance and requests the support of Member States in this regard. 89. The transmission of an urgent appeal does not exclude the transmission of the same case to the concerned State pursuant to the regular complaints procedure of the Working Group leading to the adoption of an Opinion, and it calls on States to provide it with separate replies to each of its communications. 90. The Working Group has decided to devote particular attention in 2010 to the issues of video and audio surveillance in interrogation rooms, alternatives to detention, a revision of its methods of work, and the detention of drug users. It thanks States which have responded to its questionnaire on the detention of drug users and requests others to do so. 91. With respect to the detention of migrants in an irregular situation, the Working Group again notes that their human rights are not always guaranteed. In some States detention of migrants in an irregular situation is mandatory and automatic without a necessity criteria being applied. National laws do not provide for detention to be ordered by a judge or for judicial review of the detention order. Detainees often do not enjoy the right to challenge the legality of their detention. There is no maximum length of detention established by law, which leads to prolonged or, in the worst case, potentially indefinite detention. In cases where the legal or practical obstacles for the removal of the detained migrants do not lie within their sphere of responsibility, the detainees should be released to avoid potentially indefinite detention from occurring, GE.10-10294 23