There was a touch of the Tony Blairs about David Cameron's New Year forays into social policy last week with sink estates, and this week, with troubled families.

Downing Street likes to make announcements as if these alone will lead to social change and as if no-one has ever heard of the problems. It is as if, with time running out to make his legacy and with little chance of making an impact internationally, Mr Cameron has decided he should focus on domestic policy instead.