"(a) to safeguard and promote the welfare of children within their area who are in need; and (b) so far as is consistent with that duty, to promote the upbringing of such children by their families, by providing a range and level of services appropriate to those children's needs."
"The local authority has the expertise, and the awareness of the claims upon its resources, to make the necessary judgments. The function of the court is to review the lawfulness of the local authority’s decision not to substitute its view for that of the local authority as to the appropriate level of assistance to be provided."