Emerging market evangelism is nothing new, but often it has been based on dodgy data. In the 5th century BC, for instance, Herodotus, the Greek “father of history”, produced what might be regarded as the earliest commodities note. It described “ants bigger than foxes but smaller than dogs” that were mining gold in Asia.

Under the shadow of the present US slowdown, a new version of that yarn is growing in popularity. This time, the part of the gold-producing ant is being played by the Asian consumer, who is being targeted by Western companies ranging from the makers of breakfast cereals to the producers of private jets.

Michael Dell, the all-American PC tycoon, became the latest chief executive to turn his sights east when he announced plans last week to build computers “specifically to the requirements of China and India”. Days earlier, while on a trip to Bombay, Patrick Cescau, the chief executive of Unilever, summed up the present thinking. He said that “domestic demand, the economic strength of the region and changing trade flows that are less dependent on the US” made Asia a priority.

While Kellogg's is fighting to wean Indians off their traditional cooked breakfasts and on to cereals, a host of American, Japanese and European carmakers are rushing to copy Tata's Nano, the £1,250 car designed to tempt upwardly mobile Indian families away from their motorcycles. Nokia is focused on selling handsets to the “next billion” mobile phone users, most of whom will be Indian and Chinese. Disney recently increased its stake in Bollywood's biggest film producer.

Alongside the burgeoning middle classes, Asian high-flyers are being courted. Last week Warren Buffett's NetJets, which sells timeshares in executive jets, set up shop in India. Hawking rides on private aircraft in a country where three quarters of the population live on less than 20 rupees (25p) a day may seem counter-intuitive, but today's Asian story is more compelling than Herodotus's. According to the World Bank, developing economies accounted for two thirds of global GDP growth last year, if the purchasing powers of local currencies in local markets are taken into account.

Moves to liberalise their economies have made Asian consumers richer. According to Forbes, four of the world's ten richest men are Indian. Companies that have tapped into emerging markets early have done well. Standard Chartered, the London-based bank that has concentrated for years on Asia, Africa and the Middle East, posted a 28 per cent increase in annual revenues to $11.1 billion (£5.6 billion) last month. The star performer was its Indian wholesale arm, where profits surged 91 per cent.

So, could the emerging economies drag Europe and the United States out of a serious slump? Probably not, economists say. Although smart companies will profit from the rise of Asia, the West cannot expect to be rescued by India and China. As Stephen Roach, the head of Morgan Stanley's Asian business, noted, China and India combined account for only a sixth of US demand. He said: “It's mathematically impossible to see a major decrease in US consumption being made up by the Chinese and Indians.”

Moreover, as Bob Parker, vice-chairman of Credit Suisse Asset Management, noted, emerging market growth is moderating. This year China will achieve real GDP growth of about 9 per cent, down from nearly 12 per cent in 2007. A similar fall — about 9 per cent to 7 per cent — is likely in India. If there is a serious deficiency in Asia's armour, it is a dependence on Western export markets. There are suggestions that the emerging economies may be better off forgetting about the ailing West and concentrating on trading among themselves.

Asia exports about as much to non-Asian emerging markets — Russia and Eastern Europe, the Middle East and Latin America — as it does to the US. Peter Morgan, chief Asia economist of HSBC, said: “Asia is not big enough to save the West, but emerging markets — in the East and the West — may be big enough to save themselves.”

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