Saturday Story; How does one become posh these days? Live in Essex, talk common, wear Oxfam, listen to the Spice Girls, avoid Radio 4... you know the kind of thing. In place of John's 'classless society' comes a time and place where less really is more.
Britain has its first solidly middle-class prime minister since Clem Attlee - which proves that the People's Party only needs to offer the world the soothing mores of the professional type to secure a landslide. But it is truer than ever that many people still desperately try to appear working class, though this is hardly ever true of people who have known how boring that state really is and can do anything about it. Perversely, we find the PM insisting on first-name terms in the Cabinet - a slip which will encourage people to descend into personalities rather than remember the dignity of their office. The First Lady - already a woman earning more than many small countries - wears leisure outfits which would not be out of place in the departure lounge at Gatwick.

It is time to reassure ourselves that stylishness - the essence of poshness - never dies. This proposition is not, by the way, demonstrated by the news of the royal website being visited by 12.5 million people in the past few months: the royal family has never had ton. It was, according to Professor Alan Ross of Birmingham University in 1954, "essentially non-U" to describe things as posh, though the habit was "gaining ground amongst schoolboys of all classes". His paper was reprinted in Noblesse Oblige, the class warfare manual Nancy Mitford edited in 1956, a time when everyone spoke obsessively about the classes because they recognised that society was soon to cease being divided into them.

The intervening years have seen class die, in the sense that neither advantage nor disadvantage is conferred just by people's background. To be fashionable might be all right among the very young, but its charm palls. Trendiness was born tawdry. Few can afford to be grand, in the sense that applies to some of the very rich or aristocratic, who can insulate themselves from society. Indeed, to be posh, an activity's satisfactions need to be lasting or deep, but it will be exercised by people too well mannered to want to cause disquiet to people too poor or lazy (or, more sadly, too stupid) to join in. It follows that it is difficult (though not impossible) to be posh while spending large sums of money. So the opera can be posh, but the ballet is more so.

No one who has anything to sell can make it posh, yet only a decade or two can transform a Rolls-Royce from risible vulgarity to desirability. There is nothing more posh than an English teenage girl wearing Oxfam and nothing posh at all about "It" girls who brag about their shopping. It is posh to wear good clothes which do not bear the mark of their maker on the outside.

Breeding used to matter. Not now. We all accept that the British are hopelessly mongrel, especially because our people have always married for love (very posh). The serious Catch 22 is that we have a horror of snobs. It is a mark of social failure to admit to feeling anything like social superiority. Aristocrats and barrow boys have always had an affinity, a relationship which has especially flourished since the Sixties, when so many of both classes became photographers (pace Lichfield and Bailey). Beware feeling superior about an address - Essex is posh because it is prettier than expected and because of the courage it takes to live there.

The lower middle classes, when they could still be identified, were pitied by everyone else in society for their snobbery. Their confidence has not been much improved during the decades in which they have provided our prime ministers. Being located in the muddy middle, they have found mobility hard to embrace, unlike the volatile upper and lower classes.

It is a rule of thumb that it is posh to be improvident, whatever young politicians are trying to achieve in that direction. But to plant even a hedge is posh (because it is a gift to the ungrateful future). To be interested in pensions is disastrously unposh. It smacks of self-concern, whose most deplorable manifestation is most sorts of counselling. Smoking and any self-destructive activity stands a chance of being posh, as does anything to do with horses, according to Charles Jennings in his People Like Us - A Season Among the Upper Classes, just published.

It may be a little soon for the Blair-endorsed Ford Galaxy "people mover" to dominate the Badminton horse trials this weekend; expect, however, a flurry of the vulgar Land-Rover Discovery among the far grander Defenders and Range Rovers of that marque. Though dangerous, jogging remains unposh, partly by being done in the kind of clothes Tony's Cherie affects. It is posh for a woman to use her husband's name, because it demonstrates self-abandonment. It remains a sound rule for spouses to use each other's surnames only, whatever the trend in Downing Street.

Poshness depends on quality, and thus on obduracy. It attaches to clubs whose entry fee is talent or style, but never merely money. It is about being individualist, but not bolshie. In a classless society, and one whose official religion has become the suppression of elitism, anyone trying to maintain ordinary - that is to say, high - standards is dissident and stands a fair chance of being posh.

There isn't much that the BBC does which is exceptional, but Radio 1 has become intermittently posh. Its Essential Selection on Friday evening is accepted as defining what thoughtful and savvy clubbers want to hear. It sets their agenda, not in the usual modern way of seeking the lowest common denominator, but by being satisfyingly the best. The Barbican is posh in the same way that Essex is.

Sheer exuberance ensures the Spice Girls a degree of poshness, as it does Alan Clark (whose wealth and celebrity risk damaging this claim). Besides Mr Clark, other fading beauties achieve poshness in the degree to which they have regained dignity having once thrown it away. Marianne Faithfull is a good example; Jane Birkin and Charlotte Rampling run her close. Helen Mirren is posh because although she's an actress, she often speaks excellent sense. All speak posh, which helps.

Any sensible and posh person is dismayed - genuinely disquieted - by the experience of waking up to Radio 4 in the morning. It is odd enough that government ministers have lives so empty that they want to start work at 7 or 8am. The offence of the Today programme is to contrive a blend of indigestibility and pabulum which is offensive to posh people, who are busy, so they do not want flummery. The old World Service is a better model: its quality is derived from its being equally satisfactory in ambassadorial residences and mud huts. The World Tonight comes closest.

The Week, a weekly digest of the media, is posh partly because it avoids adjectives and is very late with the news. If a thing's worth knowing, it can be expected to remain so for seven days. Matthew Parris is posh because he recognises that an aphorism is to a joke what unprotected sex is to ballroom dancing.

It is difficult to have anything to do with television and be posh, though Jon Snow's Channel 4 News comes nearest. The women on Newsnight nearly make it posh, but Jeremy Paxman's melodramatics have lowered the venue's tone beyond rescue. It is doubtful that anyone who has anything remotely interesting to do will be watching television, unless - as in the case of Channel 4 News - it amounts to a radio programme and does not interfere with preparing supper. Posh food is on the whole prepared at home, though it is posh to be so busy that one has to let someone else do it. The same principle more tenuously applies to bringing up or educating children but not to gardening, which one should do oneself.

Tesco is posher than Sainsbury because they recognise that it is retailers, not their customers, who should be aspirational. Posh eating out is difficult, though greasy spoons are possible, and the Market Cafe in Spitalfields remains a style leader. Despite its prices, The Connaught is posh, for either eating or sleeping.

By the way, it is virtually impossible that any meal eaten at home will be dinner, and safest to use the word only when evening clothes are involved. Nancy Mitford thought only pets and children could be thought of as eating dinner, in the sense of its being their "main meal", in the middle of the day. Whatever we call it, and it doesn't much matter, it is quite posh to be up so early that one's main meal is eaten early.

A prime rule of poshness used to be a pride in the Anglo-Saxon simplicities of life and speech. This led to a valuable loathing of anything French. It also led to the absurdity that the anglicised Italian word for a water closet - "lavatory" - was preferred to "toilet". This is obviously ridiculous, but anyone so perfectly spiritual that they can use the word "toilet" without shame is probably already in heaven.

Several years of Labour government may change this. It is obviously right (though for years it was thought wrong) to believe that Chanel sell perfume, not scent. Perfume is something the French make. Scent is something a respectable British fox has and hounds follow (at least for now). There are very few rules now about speech, except that everyone over 16 ought to speak as they want. Up until then, it is axiomatic and acceptable that everyone is driven to sound as common as possible.

On the whole, less is more. It is posh to be laconic. Short books are better than long ones, short films better than epics. Drawings are better than paintings (hence, the poshest galleries of all are the drawing rooms of the British Museum). Now that everyone has been everywhere and seen every natural wonder, staying at home to do a watercolour of one's window box is posh.

Warning: public displays of affection are seldom posh, and should be indulged in only when absolutely necessary for strictly private reasons.