Not that Charles has had a good time exactly, as David Aaronovitch pointed out in these pages earlier this week. He has been so burdened with a sense of duty, a pretension to intellectual seriousness and a series of impossible requirements of his sex life that he has been as securely imprisoned in misery as any member of the underclass. When it comes to the allocation of unhappiness the Royal Family is an outstanding special case among the materially privileged classes, but that does nothing to diminish the force of the argument that our life chances are overwhelmingly determined by the social circumstances of our birth.
Any parent can see how early the separation into advantaged and disadvantaged begins. The class bias in breast-feeding, in the figures for parents who "smack" children under the age of 18 months, in the extent to which reading at home is at least as normal as watching television, and in the persistent inequality of health that Sir Donald Acheson has documented - these and many other biases mean that a system of educational apartheid is already well established by the time children turn up for their nursery classes at the age of four.
There is some evidence that social mobility has increased - albeit at a glacial pace - during this century, in that many people born to working- class parents now find themselves in middle-class jobs. Indeed, the last Conservative government put some effort into trying to soften the impact of statistics showing a growing disparity of incomes, by "proving" that people moved up and down the income scales more easily than in the past. Unfortunately, the studies it commissioned made the opposite case, finding that the individuals in the bottom tenth of the income distribution at any one time might have moved up some years later, but rarely out of the bottom third.
At the top end of the scale, various professions are no longer closed shops of the privately educated, and the story of rising to the top from humble origins is an increasingly common one. John Major's journey from Brixton to Downing Street did serve as some kind of hopeful symbol. British businesses are increasingly run by people who have risen on merit (almost all men, however). Stars in sport and pop music are handsomely rewarded regardless of their background.
There are signs, then, that the barriers of class, sex and race are eroding, but far too slowly. While British politicians have spouted the language of "meritocracy" at least since Harold Wilson, they have shown little understanding of the concept.
When Michael Young invented the word in 1958, it had a negative meaning. The creative genius, who helped write Labour's 1945 manifesto and founded the Consumers Association, used it in his satire on British society. It was an attack on selection in schools and the 11-plus, in particular. Simply rewarding "ability", the egalitarian Young argued, would create an embittered underclass of the less able.
It was a curiously pessimistic vision for someone on the left and contrasts sharply with the shiny optimism of Tony Blair, who declares that, once the shackles of Old Britain are lifted, we will all "realise our true potential", with the implication that such an outcome would somehow iron out all the awkward inequalities of academic, artistic and athletic ability and earning power. However Michael, now Lord, Young made an important point, which is that a true meritocracy is not egalitarian. Indeed it would be elitist, and a good thing too. Elites, provided they are not closed castes of inherited privilege, are necessary for the functioning of a fair and efficient society.
But Young was right about one thing, and that is the centrality of education. His argument against the 11-plus carried the day, but we ended up with an embittered underclass anyway, because the real divisions in education were not tackled, in particular the most damaging divide between private and state schools. This month's most telling statistic of social division was that state school pupils achieve higher degrees at Oxford and Cambridge than their counterparts from private schools. This is proof that money can still buy an advantage in winning places at our elite universities.
Modern meritocrats, however, must accept that rewards will be unequal, while striving all the time to make them fair. In this we should be guided by "the veil of ignorance", the great idea of the liberal philosopher John Rawls. A society is fair, he argued, if it is so organised that we would accept it without knowing in advance what our place in it will be - in other words, if it is so organised that we would accept with equanimity the prospect of being born either on a council estate or in Windsor Castle.
It is one of Prince Charles's strengths that he has devoted much of his effort in public service to attempting to tackle precisely the problems of social exclusion experienced by those of less fortunate birth. We wish him a happy and inclusive birthday.