When couples split up, families move from one to two households. Poverty is a common outcome that affects children. Six out of ten lone parents are supported by the state compared to one out of ten couple parents. That's where most of the £50bn is spent.

Five years ago, the UK had the highest rate of family breakdown in Europe. We're not doing as badly today, but only because of big falls in divorce rates. Alas there's no sign of a similar improvement among cohabitees

Divorce rates have plummeted over the past 3 decades, but the number of lone parents has doubled in the same period. Why?... Because unmarried parents make up only one in five cohabiting parents but are responsible for one half of all family breakdown.

Whereas stability is the norm if parents are married (75% stay together), it is the exception if they are not (30% stay together). As a result, among parents of teens who are still together as a couple, nine out of ten are married

The single most important factor in a child’s healthy development is the stable relationship of the parents. Our groundbreaking research shows that family breakdown is the #1 predictor of teenage mental health problems.