"The number of children in care in England and Wales who have restrictions placed on their freedom has tripled in the last two years," says this article from BBC News. Deprivation of liberty orders "can cover a range of restrictions from detention in a house to taking away a mobile phone - and are commonly secured from the High Court or Court of Protection by a local authority in charge of the care of the child."
In one such case, a recent hearing "granted a deprivation of liberty order for a 13-year-old child to be detained in a rented council house while being cared for by four local authority staff."