''Always have at least one treat to look forward to. Ideally you should have one mini-treat each day, a slightly bigger one every week and a bumper one each year. People with low self-esteem rarely treat themselves enough."
So writes Gael Lindenfield, "the UK's number-one confidence expert", in the 51st of the 365 day-by-day tips that make up her bestselling Self-Esteem Bible. Contained in this nugget of advice is the key to a whole new way of looking at the British economy.
Not many people realise this (not even the British Retail Consortium, whose spokeswoman had never heard of the idea until I put it to her), but self-esteem is one of Britain's fastest-growing industries, worth at least £15bn a year and possibly as much as £30bn, compared with £8bn for the whole of what remains of British agriculture.
Products, therapies, lifestyle advisers, magazines, books and television programmes aimed at boosting self-esteem and "well-being" have become big business in themselves, not least because boosting self-esteem is now heralded as a catalyst for improved productivity in every other business sector. People with high self-esteem, it is said, are more likely to enjoy their jobs, accept challenging targets, resist stress and cope with negative events, so selling self-esteem is more than just a good wheeze for those who claim to be able to package and sell it. It is like prescribing Viagra for the whole of Britain's productive economy.
The social theorist we have to thank for this perception is Andy Westwood of the Work Foundation, whose recently published paper Me, Myself and Work (sponsored, significantly, by the Cosmetic Toiletry and Perfumery Association) sets out to examine why self-esteem is so important in our working lives today. In doing so, he provides some startling statistics. A survey of Yellow Pages directories since 1992 indicates a widespread decline in traditional shops and trades, but a 5,000 per cent increase in the number of aromatherapists. Roughly six million people in Britain pay a subscription to a private health club (though how often they visit them is another matter) and one British woman in five has attended a Weight Watchers class.
We can all confirm these trends by observation: in Helmsley, my home town in Yorkshire, we have no dispensing chemist but we do have an alternative therapies clinic offering reflexology and shiatsu; six miles away in Kirkbymoorside, the last draper's shop has just closed, to be converted into a fitness centre.
Down south, a City acquaintance tells me it is fashionable to spend your bonus on cosmetic dentistry. Michael Warshaw, chairman of the luxury bath and body products maker Molton Brown, told me his business is about "solutions to contemporary lifestyle challenges . . . People want to be cocooned."
In all walks of life, it is OK to be "needy" (meaning self-obsessed, rather than poor) and to explore New Age answers to those needs: Tony and Cherie Blair led the way in 2001 when, according to the Times, they smeared their naked bodies with mud and papaya before primal screaming in a Mexican temple.
Hold that thought, and let us consider whether this really amounts to an industry or a significant economic trend. Does it offer a smart stock-market play, in which investors should search for shares with a promising ratio of price to self-esteem? Or is it merely a passing fad based on what Frank Furedi, professor of sociology at the University of Kent, has called "the cultural myth of our times" - the idea that the pressures of modern life have made individuals more needful of reassurance about themselves?
Investors certainly don't seem to have cottoned on. Nick Bubb of Evolution Securities, the stock market's leading retail-sector analyst, told me that it has never occurred to him to monitor competition between high street giants in terms of their appeal to self-esteem: if Hennes and Mauritz of Sweden is about to take over Marks & Spencer's leadership position, it is because the Swedes offer better clothes and brighter shops rather than deeper appeal to vulnerable psyches. Boots, he points out, made a strategic move into "well-being services" not long ago that turned out a complete failure. But Bubb also let slip that he had just enjoyed an expensive holiday in India, which included an experience of Vedic massage: all but the most unreconstructed of us, it seems, have acquired the appetite for treats and treatments which Gael Lindenfield prescribes.
Another investment expert, who should perhaps remain nameless, put all this in a clearer perspective for me. Yes, she said, the middle classes have more disposable income these days and everyone likes to pamper themselves occasionally; and yes, since you've asked, health clubs have been a hot investment for the reason that they tend to make oodles of money. But retailers and services seeking to hitch their brands to the "self-esteem" bandwagon are in danger of overegging it.
"Suddenly, everything has to be an experience," she groans. "If you go to Space.NK in Notting Hill for a leg wax you just want it quick and pain-less, but you have to go through a whole ritual of fluffy bathrobes and scented candles. You go to an Aveda salon for a haircut and they insist you have a head massage first, with some 19-year-old idiot asking which oil you prefer, 'relax' or 'energise'. It just makes me want to slap them."
Aveda, by the way, makes a big splash about protecting the planet, a theme that plays well with customers who want to feel better about themselves. On that basis, you might think Anita Roddick's Body Shop would be ripe for a self-esteem-fuelled revival - but my anonymous investment expert-cum-shopper tells me the brand is now too mainstream to catch the wave; the newcomer to watch in the "natural cosmetics lifestyle brand" stakes is Lush, maker of Buffy the Backside Slayer Body Butter - which is definitely on my Christmas present list. But back to the serious arguments.
Clearly there is something going on in consumer markets, and it might be a response to a national epidemic of low self-esteem. Or it may be something much simpler: people have more money and time to spare for luxuries, and can overcome the guilt associated with luxuries by being persuaded that it helps address an inadequacy they did not realise was there in the first place.
A recent research exercise by Bridgepoint, the private equity firm, points out that while personal spending on food and clothing has remained relatively stable since 1978, spending on "leisure services" has more than tripled, partly because consumers no longer see any point in saving. As to how that leisure spend is allocated, focus groups say they are less interested in lifestyle brands and more interested in bargains (on eBay, for example) or treats: but the treat they value most is nothing more complicated than a bit of peace and quiet in the midst of their increasingly busy lives.
So I incline to the view that, as a framework for studying consumer behaviour, the self-esteem theory contains quite a high proportion of hot air and marketing hype. But Westwood disagrees; he goes as far as to argue that the self-esteem "industry" deserves government support because it offers a unique form of insurance against insecurity about jobs, money and personal circumstances, helping us collectively to maintain our competitive edge in a changing world.
A cynic might respond that an economy which has lost swathes of businesses in its manufacturing and farming industries while enjoying an 800 per cent increase in the "male grooming market" since 1998 is an economy that has lost all appetite for competitiveness and given way to self-indulgence. If we are keener on moisturising than on making goods and growing food, perhaps it is not worth investing in us at all.
It would be unfair to leave the subject at this point, however: there is another aspect of Westwood's analysis that deserves attention - and it is as far removed as could be from the world of Notting Hill salons and primal screaming holidays, not to mention Vanessa Feltz's Cosmetic Surgery Live.
For yuppies, self-esteem deficit syndrome may be a largely imaginary excuse for shopping, but for those who are poor, jobless and have been failed by the state education system, it is much more real. Step forward here an unlikely hero of this story, though a keen adherent of alternative therapies: the Prince of Wales.
When he was criticised in November for appearing to suggest, in a leaked memo, that children with little talent would do better to have a little less aspiration, his defenders pointed out that through his charity, the Prince's Trust, he has probably done more than anyone else in Britain over the past three decades to boost the self-worth and aspiration of young people on the edge of society - more than half a million of them.
Earlier this year I watched for myself, at an after-school club for underachievers in a Burnley comprehensive and on a training course for 18- to 25-year-olds at the Bolton YMCA, how the trick is done. The key is to find a kernel of self-esteem in kids who would otherwise think of themselves as social rejects and no-hopers, and would most likely turn to drugs and crime.
To the extent that the trust's self-esteem coaching makes troubled youngsters revalue themselves and become productive members of society, Westwood's thesis stands proud. However, it would be wise not to overload it with psychobabble about middle-class shopping habits.
Meanwhile, more from Gael Lindenfield. Eighty-three: buy yourself a small book of motivational quotations. Ninety-nine: think of yourself as a product for sale. One hundred and seventeen: like celebrities, transform your appearance regularly. And finally, if Christmas shopping is getting you down, 119: imagine that you have three weeks to live.