Local authorities have overarching responsibility for safeguarding and promoting the welfare of all children and young people in their area. They have a number of statutory  functions under the 1989 and 2004 Children Acts which make this clear, and this guidance sets these out in detail. This includes specific duties in relation to children in need and children suffering, or likely to suffer, significant harm, regardless of where they are found, under sections 17 and 47 of the Children Act 1989.  Whilst local authorities play a lead role, safeguarding children and protecting them from harm is everyone’s responsibility. Everyone who comes into contact with children and  families has a role to play.

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/419595/Working_Together_to_Safeguard_Children.pdf