A new book has been causing a bit of a stir in policy circles in the UK – ‘The Spirit Level’ is not another diatribe for or against God, as the name might suggest, but a book about equality.

The main message is fairly simple – affluent societies tend to suffer social ills like mental health problems, drug use, physical health, obesity, educational problems, teenage births, violence and crime in direction correlation to how equal or unequal they are. And people are unhappier too. Once you get above about $25,000 per capita GDP, the relationship between rising affluence and rising welfare disappears and is replaced by equality rather than affluence.And perhaps their most startling conclusion is that in more unequal affluent societies everyone suffers more from ill-health and other social ills, not just the poor. The data and analysis is piled on throughout the book and is difficult to dispute.

‘The Spirit Level’ is published at just the right moment as a huge debate about the future direction of western societies is opening up as a consequence of the current crisis.

Perhaps the only weak-spot of the book is the discussion of policy options. The authors stress that the more equal societies suggest there are multiple ways to achieve more equality. Whilst the Scandinavian social-democratic states have relied on heavy, progressive, taxation and redistributive social policies, Japan achieves high levels of equality through cultural norms. But the book is a bit neutral about actual policy choices. But if you are looking for an argument to justify restricting obscene levels of bonuses which massively widen inequalities then this is the book for you.

To read some of the evidence see The Equality Trust website