E/CN.4/1999/63/Add.3 page 7 have more incentives to comply with restrictions imposed, if released, than one who faces early removal. Special consideration to release is given to such asylum applicants who have brought themselves to the attention of the authorities at the first reasonable opportunity. Port applicants who seek asylum at the outset of their examination and illegal entrants who bring themselves to notice when seeking asylum soon after arrival would perhaps have the benefit of consideration of release, as distinct from those who seek to enter clandestinely. But where the application is judged to be without foundation and in cases where the applicant has come from a safe third country, the presumption that the individual should be released unless there are strong countervailing factors may not apply. Yet, detention is to be authorized only when it is judged essential to do so. 13. Paragraphs 16 to 18 of Schedule 2 of the Immigration Act, 1971 cited above, do not indicate the criteria on the basis of which the immigration officer is entitled to refuse entry of persons who seek asylum in the United Kingdom. The guidelines are in the nature of instructions but have no statutory force. Nor is an asylum seeker informed at the outset of the reasons for the denial of entry in writing. The July 1998 White Paper envisages a legal regime and appropriate amendments pursuant to which an asylum seeker will be informed of reasons for denial of entry in writing at the first instance. C. Procedural aspects and comments thereon 14. Once the immigration officer refuses entry to a person seeking asylum, the person is thereafter dealt with by officials of the Home Office who then decide, after recording the statement of the person concerned, whether or not to detain him. The functioning of the legal regime in the context of detention is at present guided by practical considerations relating to the availability of spaces for detention. Of the approximately 1,000 spaces where detainees may be placed at any given time, only 850 are available for use. Almost half of these spaces are either in the prisons at Rochester and Wormwood Scrubs, and at Haslar HOHC; the other half are in separate designated detention centres at Campsfield, Harmondsworth and Tinsley House. 15. At any given time the number of persons seeking entry to the United Kingdom is far larger than the number of persons who can be detained, given the limited space available (the number of persons who sought entry in 1997 exceeded 32,000). In a given year, about 20,000-25,000 persons seeking asylum are removed immediately. Accordingly, the Group was informed, about 1-1.5 per cent of the total number of persons seeking asylum are detained at any given time. The following table shows the number of detained persons as of 29 May 1998 and 1 June 1998.