In 2013 the benefit cap was introduced, placing an absolute limit on the support any one household can receive. Households with children are disproportionately affected with more than 175,000 children caught by the cap. There are concerns about the likely impact of the cap on vulnerable children, including those in temporary accommodation and ‘children in need’. This report of research by Action for Children, based on freedom of information requests, reveals that only 1 in 10 local authorities in England know how many children in need are affected by the benefit cap. The research also reveals a worrying lack of joined up working between housing and children’s services departments and a continued reliance, by local authorities, on temporary accommodation.