“Everyone has the right to liberty and security of person. No one shall be deprived of his liberty save in the following cases and in accordance with a procedure prescribed by law: … (f) the lawful arrest or detention of a person to prevent his effecting an unauthorised entry into the country or of a person against whom action is being taken with a view to deportation or extradition.”
"46. There is no dispute as to the principles that fall to be applied in the present case. They were stated by Woolf J in Hardial Singh[1984] 1 WLR 704 , 706D in the passage quoted by Simon Brown LJ at paragraph 9 above. This statement was approved by Lord Browne-Wilkinson in Tan Te Lam v Tai A Chau Detention Centre[1997] AC 97 , 111A-D in the passage quoted by Simon Brown LJ at paragraph 12 above. In my judgment, Mr Robb correctly submitted that the following four principles emerge: i) The Secretary of State must intend to deport the person and can only use the power to detain for that purpose; ii) The deportee may only be detained for a period that is reasonable in all the circumstances; iii) If, before the expiry of the reasonable period, it becomes apparent that the Secretary of State will not be able to effect deportation within that reasonable period, he should not seek to exercise the power of detention; iv) The Secretary of State should act with the reasonable diligence and expedition to effect removal. 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."
"In those circumstances, for continued detention to be lawful two questions have to be capable of being answered. First, by when does the Secretary of State expect to be able to deport A? Secondly, what is the basis for that expectation?"