In this speeded-up world, it doesn't take long for something to become a classic. The Cornetto, once a byword for synthetic modern living, is being marketed as a timeless masterpiece, to set alongside its brash, new spin-off, the Cornetto Whippy. Like "new" Coke and "classic" Coke, we now have "new" Cornetto and Cornetto "classico". And, like the Coca-Cola marketing disaster of the 1980s, it is hard to see why they bothered.

The Whippy, which was launched in April this year, is sold in supermarkets, newsagents, cinema foyers and from ice-cream vans, just like the original Cornetto. It comes in a shiny blue wrapper and keeps for several weeks in the freezer. But everything else about it seems designed to suggest that you are eating not a Cornetto, but a 99 Flake. It is a very bizarre product: a fake version of something - Mr Whippy ice cream - that is already fake, in contrast to something, the Classico, which is also fake, but has been fake for longer.

Cornetto Whippy looks like an ice cream that might be eaten by Tom and Jerry. It is authentically pretend. With its candyfloss-like aureole (contained in a little plastic dome), its plastic-looking chocolate stick and its too-neat criss-crossed sugar cone, it might have come out of a pop art print. It is an idea of ice cream, not ice cream itself. Yet the thing that makes cartoon food seem so delectable is that you know you will never taste it. In the case of the Cornetto Whippy, this would be a good thing. Once you move from the idea to the reality, it's all disappointment.

The ice cream part is made from concentrated skimmed milk, sugar, glucose syrup, butter oil, emulsifier (E471), stabiliser (E401) and flavouring. It tastes even worse than this ingredient list suggests. There is a sort of debased, coconutty quality to it, and it sits disturbingly on the tongue. What's more, because so much air is pumped into it to produce the "soft-style" effect, the Whippy seems almost warm, even when you take it straight out of the freezer. The chocolate stick is not a Cadbury's Flake, but a more solid, Aero-like concoction, with a sticky, gum-adhering quality. I can't imagine anything less refreshing to eat on a hot summer day.

By comparison, the original chocolate and hazelnut Cornetto Classico is quite palatable. The Cornetto is possibly the most successful ice-cream cone in the world, as recounted in Licks, Sticks and Bricks: a world history of ice cream (1999) by Pim Reinders - the Unilever story. The crucial technology was working out how to make a cone that would stay crisp in the freezer. It was discovered, as the "Just one Cornetto" ads didn't quite tell us, in Eeeetalee in 1959. The Italian ice-cream firm Spica dipped a cone in a mixture of oil, sugar and chocolate. This insulating coating prevented the ice cream from coming in contact with the wafer and softening it. And so the Cornetto was born. It was not long before Unilever spotted the idea, took over Spica, and launched the Cornetto all over Europe in various flavours. In Spain, the company even did a kiwi-fruit version.

But what made Unilever decide that the ice-cream eaters of the world now need an ersatz version of Mr Softee? I phoned the PR department of Birds Eye Wall's (an offshoot of Unilever) to find out.

My conversation with the charming representative was like one of those games where one person has to avoid saying "yes" or "no" to anything, and the other person has to try their damnedest to make them crack. In this case, the ebullient Wall's representative on the phone stuck heroically to the phrase "I can't answer that". Who thought of the idea for the Whippy? "I can't answer that." How was it developed? "I can't answer that." Is it being made internationally? "I can't answer that." Is it an attempt to undermine the business of Mr Whippy ice-cream vans? "I can't answer that." After about the fifth time that she had said "I can't answer that", she added a triumphant giggle at the end, to let me know the game was up. Her voice indicated she was a mere cog in the enormous machine that is Unilever, but that this machine itself was so immense, even a cog had the power to crush any insignificant object that stood in its way. Eventually, she even began to feel sorry for me.

"You could ask me to describe it, if you like." OK, then. "Well, it's got a chocolate flake in it and is quite soft." But I knew that already. What else could I ask you? "Well, you could ask why we launched it." Yes! At last! A question to which I might get a real answer! "Well, from consumer research, we found that there was a gap in the market for this sort of ice cream." Emboldened by this crumb of information, I asked what the initial sales figures were like. "I'm afraid I really can't answer that," she said, "but I can tell you the Whippy is doing very very well."

O sole mio, I hope she's wrong.