217.—Any person who knowingly harbours, maintains or conceals F199[a child, or a person other than a child who has escaped when a child from lawful custody within the meaning of section 215(1), or otherwise prevents a child or such an escaped person] from returning to a children detention school or to any person with whom he or she has been placed out on supervision in the community shall be guilty of an offence and shall be liable, on summary conviction, to a fine not exceeding £750 or imprisonment for a term not exceeding 6 months or both.