Happiness is a real, objective phenomenon, scientifically verifiable. That means people and whole societies can now be measured over time and compared accurately with one another. Causes and cures for unhappiness can be quantified.

There is all the difference in the world between teaching children about religion and handing them over to be taught by the religious.

Nothing keeps people together like the exalted conviction that they alone are to be spared that eternal anguish of hell fire to which everyone else will be condemned.

This is indeed a clash of civilisations, not between Islam and Christendom but between reason and superstition.

But the single overwhelming reason why jails are bursting is longer sentences given for more crimes.

Is anyone serious about the politics of happiness? David Cameron dipped a toe in the water, using the word lightly, but denying the hard policies it implies. Labour shies away from it, but should take up the challenge.

Inequality makes everyone unhappy, the poor most of all, and that is well within the remit of the state. More money gives less extra happiness the richer we get, yet we are addicted to earning and spending more every year.