Does "child" include "step-child"? That the Housing Act specifically defines "child" as including "stepchild" makes me wonder.
S 113 of the 1985 Housing Act provides: “Members of a person’s family. (1) A person is a member of another’s family within the meaning of this Part if— (a) he is the spouse or civil partner of that person, or he and that person live together as husband and wife or as if they were civil partners, or (b) he is that person’s parent, grandparent, child, grandchild, brother, sister, uncle, aunt, nephew or niece. (2) For the purpose of sub-section (1)(b)— (a) a relationship by marriage or civil partnership shall be treated as a relationship by blood, (b) a relationship of the half-blood shall be treated as a relationship of the whole blood, (c) the stepchild of a person shall be treated as his child, and (d) an illegitimate child shall be treated as the legitimate child of his mother and reputed father.”
Ward LJ said
When Parliament wished to extend the meaning to cover de facto relationships, it did so expressly, for example by defining “spouse or civil partner” to include those who live together as husband and wife or as if they were civil partners. Absent such amplification, there was no room for extending the meaning of a “child” to cover a foster child
http://www.lawreports.co.uk/WLRD/2010/CACiv/SheffieldCC_v_Wall.html