Academics Dr Sabina Garahan and Dr Matthew Gillet argue, “by allowing detention for such period as ‘in the opinion of the Secretary of State’ is reasonably necessary, section 12(1)(b) conflicts with fundamental standards 133 Explanatory notes, para.44 134 There is a time limit of 24 hours for detaining unaccompanied children in a short- term holding facility (Immigration Act 1971, Schedule 2, paragraph 18B inserted by the Immigration Act 2014). There is a 72-hour time-limit or not more than seven days where a longer period of detention of a is authorised personally by a Minister of the Crown, of pregnant women (Immigration Act 2016, s 60) and of accompanied children and their families in pre-departure accommodation (Immigration Act 2014, s 6). 135 JCHR, Legislative Scrutiny: Illegal Migration Bill 12th Report of 2022–2023, paras 194–202 136 Professor Sarah Singer, Q6 38 of legal certainty, since the “opinion of the Secretary of State” is neither foreseeable nor open to legal challenge.” It would, of course, be open to challenge on public law grounds, such as irrationality.