It may often be the case that a foreign individual irregularly staying in Poland is placed in detention for the very purpose of establishing identity and nationality. In such a situation, it is crucial that detention is subject to regular review and that the decision on prolongation of this measure is only taken upon a careful assessment of the grounds and necessity of detention. For the purposes of this study, an analysis of data concerning migration detention was carried out with a view to providing an answer to the question whether stateless persons with irregular status are typically detained and whether there are any identifiable statistical differences between stateless persons and third country nationals in this respect. An analysis of statistical sources provides insufficient data to fully support the assumption that stateless persons are more likely to be detained than other irregular migrants. However, some other observations can be made. Various categorizations are used in relation to the group of foreigners whose nationality is in some way disputed. These different terms may overlap and, in fact, describe the same situations, creating a non-exclusive set of subgroups, which is both confusing and unhelpful in understanding the nature and scope of statelessness. In many cases, the status of those persons often leads to those persons being detained, due to the lack of documentation certifying their personal data. Some of the categories listed by the statistics provided by the Border Guard service include the following: nn persons lacking identity documents; nn persons determined to be stateless; nn stateless persons claiming to be citizens of a given state; nn persons not claiming to have any nationality; nn persons whose nationality and origin has not been confirmed; nn persons whose nationality is unknown; nn persons whose identity has not been confirmed, but who are claiming to be citizens of a given state. These multiple categories may lead to confusion. It is difficult to argue that there is an added value in separating the category of persons lacking identity documents from the category of persons whose identity/nationality has not been confirmed, since a foreigner without identity documents will often – as follows from observations from research and legal practice – be seen prima facie as a person without a proper confirmation of his or her identity. It is also self-explanatory that when there is a lack of documents, the authorities will need to determine the identity and nationality of the individual by other means. Thus, at a certain point, some persons from this category will also be “claiming a certain nationality” or “claiming to be stateless” which makes this distinction redundant. On the other hand, persons for whom the country of origin does not take any position in relation to their nationality after a certain reasonable deadline should, depending on the circumstances, be recorded as stateless or “at risk of statelessness” at the very least.94 Once a positive decision on the nationality is issued, this categorization would be subject to change. This statistical categorization shows that the very core characteristic of statelessness as a non-permanent status is not taken into consideration. It is also crucial to stress that the process of establishing nationality in a situation where there is a risk of statelessness usually bears immediate, negative consequences for the individual, as it may prolong one’s detention. 94 34 See UNHCR, Handbook on Protection of Stateless Persons, cited above, para. 41. MAPPING STATELESSNESS IN POLAND