DEMOB happy, Tony Little, the soon-to-be ex-head of Eton College, has written a book.

It is called An Intelligent Person's Guide to Education and until it is published in the middle of next month we must make do with the extracts that have appeared in a newspaper.

In the latest of these, Mr Little offered his ten golden rules on how to be an Etonian. These ranged from the commonsensical ("be ambitious, not arrogant", "be sanguine in the face of a crisis") to the frankly crackpot ("ask for an audience with the Dalai Lama", "befriend a politician", "cross-dress occasionally"). For nuggets such as these parents queue eagerly round the block to pay fees in the region of £35,000 a year.

I thought of Mr Little and Eton when I read of a report from the Social Mobility and Child Poverty Commission which bemoans the fact working-class candidates for jobs with numerous "leading" firms are judged - and inevitably found wanting - by the clothes they wear, how they speak, and by their manners.

Moreover, the Commission also revealed top law and accountancy firms recruit from the shallowest of pools, preferring to take those who attended private or selective schools or come from affluent families rather than those who - pace Old Fettesian Tony Blair - emerged from "bog standard comprehensives" and succeeded despite manifold disadvantages.

Said the Commission's chairman, Alan Milburn, the former Labour health secretary: "This research shows that young people with working-class backgrounds are being systematically locked out of top jobs. Elite firms seem to require applicants to pass a 'poshness test' to gain entry."

There is, of course, nothing surprising in this. As is obvious to all but the ideologically myopic, social mobility is a myth promoted by politicians and the so-called upper classes to encourage us to believe Britain is a meritocracy in which those who have talent and intelligence and who are prepared to work their socks off will rise to the top.

Some, I dare say, do. But a much easier and more predictable route to upward mobility is to ensure you are born with a silver spoon in your mouth and that your mother and father have the necessary income to have you educated in an establishment where you are not likely to come into contact with hoi polloi.

Edinburgh, needless to say, is the capital of posh. There, around one child in four is privately educated. Parents vie to get their offspring into the "best" schools, sure in the knowledge the more selective the intake - ie the higher the fees - the better the connections.

It has long been thus and nothing is likely to change imminently. To outsiders, it is a matter of some bemusement. Two American friends are fond of relating how, at a New Town dinner party, the conversation turned as it inevitably does to schools, whereupon they were asked which one their children attended. Immediately, they realised this was a none too subtle method of gauging where they stood in the societal pecking order. They thought they had the perfect response, because they did not have any children of a suitable age. "But," countered their hosts, "which school would you send your children to?"

You always know in Edinburgh when you've entered a posh reservation. These may not be gated communities but they are just as segregated. In such circles, the men boast of the underwear they've inherited from deceased relatives and the women make the Queen sound common.

Many live in decrepit piles they can't afford to heat, often because of the fees they're paying to keep their children incarcerated in boarding schools. Once in one, I was given a rug to keep my knees warm over a preprandial drink. Hereabouts the thought of independence makes gorges rise and any mention of the SNP is guaranteed to prompt frothing at the mouth and incendiary allusions to fascism and communism. There is much talk, too, of upping sticks and moving to Tewkesbury or Totnes, where the grass is apparently greener and property prices are rising nicely.

Few in this milieu give a damn about social mobility. To the selfishly privileged, what's paramount is protecting what they feel is rightfully theirs. Nepotism and the Old School Tie ensure that as far as possible the status quo pertains.

What you can do is irrelevant compared to where you come from and who you know. Accent, manners and dress are part of a complex code. Break it and, who knows, you may yet have your tete-a-tete with the Dalai Lama.