Hidden truth, by Malcolm Gluck

Car advertising, for example, may well trade on illusion, status and imagery, but nevertheless the product will take you from A to B. Apparel and shoe advertising may play on the label or the perceived glamour of its wearers, but no one can deny that clothes provide somewhere to hide your money and conceal your private parts, and who goes shoeless these days? Food ads may strike absurd and declamatory poses, but we need the stuff to get through a working day. Even the vomitory superficiality of perfume advertising offers a product that will make you smell different. And so it goes.

Advertising may be the patina here, but these products have an effect that cannot be gainsaid. Further, many of the individual brands within these categories will have a singularity of design or performance which may make them different from each of their competitors.

None of this applies to any alcohol. Try as hard as you like, you cannot find any substance in any drink advertisement. Of course, a drink may major on its provenance, be it an Australian or Irish or Belgian beer, a Kentucky bourbon or a Scottish whisky; it may feature genuinely hoary employees to give an impression of a handcrafted product, but these are mere props to the preposterousness of the promise. An advertiser may offer you an ingredient, such as a rare hop or water from a particular stream, or, in the case of a hybrid or a cocktail, the very nature of its primary parts (rum, coffee, oranges, cream), but this is just the excuse for associated imagery, which is always fantasy. The bloke who wrote Heineken Refreshes The Parts Other Beers Cannot Reach' - he had the office down the corridor from me - wrote nonsense, but it was a stroke of advertising genius.

A drink is alcohol, and whether it is Chteau Lafite or Stella Artois or Rmy Martin, there are dozens of similar drinks that do precisely the same thing in precisely the same way. What gives each of those products its cachet has been shrewd marketing, clever advertising, brilliant image manipulation. If you remove these latter activities from the product, you are left with an empty glass. With alcoholic drinks the image is everything. And why? Why have drinks managed to secure an exclusive corner all to themselves where imagery is the absolute ruler? Because nothing marks out a man or a woman so much, nothing nails them so compellingly as a cool kid, a connoisseur, an aristocrat of taste, an aficionado of the hop or the grape, as that bottle (with its label so prominent) on the table or in the wine bar, pub or restaurant. Long before clothes designers stuck their labels on the outside of their products, the manufacturers of alcohol were doing it, and doing it brilliantly. Wines and spirits are two of the very few products we can serve at home that immediately reinforce to our guests the kind of person we wish to be perceived to be. The label on the bottle also labels the purchaser.

For decades this phenomenon was closely and jealously observed by the marketeers of draught beers, ales, stouts and lagers. How could one of these products achieve cult status unless it was obvious, when the drinker was drinking it outside the home, which drink it was? Only Guinness had special claims here, being black. And in fact for many years, via anguished briefs to its ad agencies, it directed them to overcome this characterisitic, which was perceived to give it an old-fashioned image. The results were years of feeble advertising. Where once the historic Guinness is Good for You' ruled, to be judged misleading by the authorities and deposed by new regulations, we had campaigns desperately trying to make the brand hip. Ernest Saunders, when he ran Guinness, ripped up a proposed ad campaign in front of its author, because it was based on the proposition that unlike any other beer You Can't See Through It'. The campaign was spectacularly off-brief because the visionary Saunders had the ambition of transforming Guinness into an international umbrella brand with aspirational products like Dunhill. He failed. The author failed. I know. I was that author.

Guinness is a dark and bitter memory for this columnist, but it taught me one thing: never make it easy for the client (editor, publisher, bank manager et al.) to say no. And one sure way never to hear that crushing No!' is to present fantasy.

• Harpers Says...