E/CN.4/1999/63/Add.3 page 12 country and the subsequent processing of documentation take several months, during which the person continues to be detained. This is another area which requires looking into. 25. Though the mandate of the Working Group relates to the scrutiny of the applicable legal regime in the context of the detention of immigrants and asylum seekers, the Working Group wishes to note that the detainees it visited, both in prisons and in detention centres, were kept in conditions that were humane and consistent with international legal standards, and that the United Kingdom authorities made an effort to create an environment for the detainees that was consistent with basic human rights. V. CONCLUSIONS AND RECOMMENDATIONS 26. The Government should ensure that detention of asylum seekers is resorted to only for reasons recognized as legitimate under international standards and only when other measures will not suffice; detention should be for the shortest possible period. 27. At the time of detention, detainees should be provided in writing, in a language they understand, with the reasons for detention. 28. At the time of detention, detainees should be provided with a written explanation of their rights and how to exercise them. 29. Each decision to detain should be reviewed as to its necessity and its compliance with international legal standards by means of a prompt, oral hearing by a court or similar competent independent and impartial review, accompanied by the appropriate provision of legal aid. In the event that continued detention is authorized, detainees should be able to initiate further challenges against the reasons for detention. 30. Detainees should be held in special immigration detention centres in conditions appropriate to their status and not with persons charged with or convicted of criminal offences (unless so charged or convicted themselves). 31. Detainees should be given adequate access to their legal representatives, relatives and officials of the Office of the United Nations High Commissioner for Refugees. 32. The Government should concentrate the use of detention on appropriate cases of rejected asylum seekers at the end of the asylum determination process (i.e. when the incentive to abscond is increased) or where removal is imminent and there are reasons to believe it cannot be effected unless the individual is detained. The power to detain should not be exercised if the person concerned is, on the basis of substantiated evidence, fully absorbed into the society from which his removal is sought. The relevant Schedules of the Immigration Act should spell out permissible criteria for detention. 33. Alternative and non-custodial measures, such as reporting requirements, should always be considered before resorting to detention.