“47 Principles (ii) and (iii) are conceptually distinct. Principle (ii) is that the Secretary of State may not lawfully detain a person “pending removal” for longer than a reasonable period. Once a reasonable period has expired, the detained person must be released. But there may be circumstances where, although a reasonable period has not yet expired, it becomes clear that the Secretary of State will not be able to deport the detained person within a reasonable period. In that event, principle (iii) applies. Thus, once it becomes apparent that the Secretary of State will not be able to effect the deportation within a reasonable period, the detention becomes unlawful even if the reasonable period has not yet expired. 48 It is not possible or desirable to produce an exhaustive list of all the circumstances that are or may be relevant to the question of how long it is reasonable for the Secretary of State to detain a person pending deportation pursuant to paragraph 2(3) of schedule 3 to theImmigration Act 1971 . But in my view they include at least: the length of the period of detention; the nature of the obstacles which stand in the path of the Secretary of State preventing a deportation; the diligence, speed and effectiveness of the steps taken by the Secretary of State to surmount such obstacles; the conditions in which the detained person is being kept; the effect of detention on him and his family; the risk that if he is released from detention he will abscond; and the danger that, if released, he will commit criminal offences.”
“103. A convenient starting point is to determine whether, and if so when, there is a realistic prospect that deportation will take place. As I said at para 47 of my judgment in R (I), there may be situations where, although a reasonable period has not yet expired, it becomes clear that the Secretary of State will not be able to deport the detained person within a period that is reasonable in all the circumstances, having regard in particular to time that the person has already spent in detention. I deal below with the factors which are relevant to a determination of a reasonable period. But if there is no realistic prospect that deportation will take place within a reasonable time, then continued detention is unlawful.”