“a) The relevant power to detain must only be used for the specific purpose for which it is authorised. This means that a person may only be detained under immigration powers for the purpose of preventing his unauthorised entry or with a view to his removal (not necessarily deportation). Detention for other purposes, where detention is not for the purposes of preventing unauthorised entry or effecting the removal of the individual concerned, is not compatible with Article 5 and would be unlawful in domestic law……; b) The detention may only continue for a period that is reasonable in all the circumstances for the specific purpose; c) If before the expiry of the reasonable period it becomes apparent that the purpose of the power, for example, removal, cannot be effected within that reasonable period, the power to detain should not be exercised; d) The detaining authority (be it the immigration officer or the Secretary of State) should act with reasonable diligence and expedition to effect removal (or whatever the purpose of the power in question is.)”
“(2) Where a deportation order is in force against any person, he may be detained under the authority of the Secretary of State pending his removal or departure from the United Kingdom….” (Emphasis added.)