That article is worth quoting at length:
David Cameron has announced that he wants to abolish housing benefit for 380,000 people under 25. The prime minister's view is simple: if you can't afford the rent, you must live with your parents. The only exception will be for children who are victims of domestic abuse.
Let us stop and think about this for a moment. An obligation on "children" to live with their parents is an obligation on parents to house their children until they are 25. What penalty does Cameron propose for parents who refuse to take in their 24-year-old child? If a couple separate when their children are in their 20s, which parent is liable to accommodate the children if necessary?
Cameron needs to explain what will happen to people whose parents refuse to house them. If a parent refuses to house a 15-year-old child, the child is taken into care. They may be placed in a children's home, fostered or put up for adoption. Is Cameron proposing that the state tries to arrange foster care for 23-year-olds? Place them in children's homes? The mind boggles at the thought of social services interviewing people about their application to adopt a 24-year-old. The cost to the state would be immense.
Cameron also needs to tell us what happens to married people aged under 25. Is he proposing a legal obligation on parents to house their sons-in-law and daughters-in-law as well as their own children? Or is he proposing that any young married couple should be forced to split up if they can't afford the rent, and return to their own parents? It is hard to imagine that the Tory party really wants to destroy marriages in this way. What happens if the young couple have children? Do parents now have an obligation to house not only their children and their children-in-law, but their grandchildren as well?It's author? Tim Leunig, recently appointed as an adviser to Michael Gove.
Thanks to @patrickjbutler for reminding me of this.