It is a pity that David Cameron could not find time for a trip to Bhutan to launch his new initiative to promote happiness. The Tory party leader's commitment to "general well-being" (GWB) instantly brings to mind the Himalayan kingdom's measure of "gross national happiness".

Bhutan is of course an absolute monarchy so its political experience cannot be transferred seamlessly to democracies. For elected politicians, a government commitment to popular happiness is altogether a more hazardous enterprise. Thomas Jefferson, who drafted the American Declaration of Independence in 1776, understood this all too well. He wisely described the pursuit of happiness - rather than its achievement - as an inalienable right.