In Re D [2019] UKSC 42, the Supreme Court has held (by a majority) that where a 16 or 17 year old child cannot (or does not) give their own consent to circumstances satisfying the ‘acid test’ in Cheshire West, and if state either knows or ought to know of the circumstances, then the child is to be seen as deprived of their liberty for purposes of Article 5 European Convention of Human Rights, and requires the protections afforded by that Article. That is so whether or not their parent(s) are either seeking to consent to those arrangements if imposed by others or directly implementing them themselves.
Read full piece at source: Re D – the Supreme Court, 16/17 year olds and confinement