So what really works? Treatments in jail do some good, but it's mostly too late: finding a family and a job or just growing older make most prisoners eventually give up crime.

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.

Thresholds of pain, indignity and incapacity are entirely personal.

Could a government dare to set out with happiness as its goal? Now that there are accepted scientific proofs, it would be easy to audit the progress of national happiness annually, just as we monitor money and GDP.

So what really works? Treatments in jail do some good, but it's mostly too late: finding a family and a job or just growing older make most prisoners eventually give up crime.

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

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.