One monstrous tower was designed in four days on a computer in a kitchen by Shenzhen architects

Rem Koolhaas, journalist-turned-architect, superstar among the young, bright and hip, was at the Royal College of Art in London last week talking in a series of lectures called "Disturbanisms", hosted by the bright and ebullient Nigel Coates, professor of architecture and design. Speaking to a crowded audience, Koolhaas really did have a disturbing tale to tell.

Over the past couple of years he has been guiding his students at Harvard through a research course that has put the Pearl River delta under the microscope. The Pearl River delta? The long fingers of water that flow more than 100 miles from the mountain ranges of Canton to the South China Sea. The Chinese call the river Zhu Jiang.

Over the past 10 years, as Koolhaas coolly pointed out, the Pearl River delta has become the fastest growing urban construct in the world. Within a few more years, the east and west banks of the broad-hipped river will be linked by a 50-mile bridge (under construction) and the mightiest of all megalopolises will have been formed.

The starting point for this unprecedented urbanisation is Hong Kong. On top of Hong Kong is Shenzhen, a "parasite" city set to cash in on its host's fortunes as Britain hands the colony over to Beijing this summer.

Shenzhen, Koolhaas told us, was a fishing "village" of a mere 100,000 peasants (and police) in 1978 when Deng Xiao-Ping, China's late "supreme leader", announced to a presumably disconcerted people: "To get rich is glorious". Even Mrs Thatcher was a year behind this most capitalist of Communists.

Today, Shenzhen has a population of 3 million and rising, and is a city of immense tower blocks, vast multi-storey car parks and titanic shopping malls. Its stupendous skyline rises, Manhattan-like, over what looked like a reproduction of Central Park in Koolhaas's slides, but is, in fact, a green belt composed of at least 500 24-hour golf courses.

To build so much in 10 years, Koolhaas said, with only a hint of a smile, has required Chinese architects to be "1,000 times more efficient than their British counterparts". A thousand times: how can he be so sure? Because the figures are there to prove it. The ratio of architects per head of the population is minute in China (1:4,500,000 in some provinces); Chinese architects produce an enormous number of buildings; they are paid very little. The net result is the most productive and, in strictly capitalist terms, the most efficient in the world.

The buildings are, of course, horrific, if fascinating. Yes, they are horrific. Not surprisingly when, as Koolhaas informed us, one particularly monstrous tower was designed in four days on a computer in the kitchen, by a team of newly qualified Shenzhen architects. Into these buildings and the vast avenues they loom over are decanted hundreds of thousands of peasants who one moment are ankle-deep in water tending paddy fields, and the next are dressed in Mickey Mouse T-shirts, eating McDonalds, and with their shell-likes glued to mobile phones.

By the end of the decade, there will 40 million people living in this unprecedented conurbation. By then, many may well have enough spare cash to buy a car and to drive to the many theme parks that are being planned as entertainment for the post-Mao masses. One of these will be a full- scale reproduction of Venice in an updated style, by the Japanese architect Irata Isozaki, who won the Royal Gold Medal for Architecture for slightly more subtle designs little more than a decade ago, when Shenzhen was still a fishing village.

It does seem fantastic (but perhaps we should be grateful) that in Britain we can argue for years and even decades over the design and construction of a single office tower (even when designed by some of the world's finest architects). In the Pearl delta they say, "let a thousand towers bloom". Are they getting it wrong? Much depends on what newly created citizens want or expect from life. In Britain it has taken more than 200 years for peasants turned urban workers to eat hamburgers, shop in air-conditioned malls and shout into mobile phones. In Shenzhen the same process has taken a little more than a decade. In 1978, 19 per cent of the Chinese population lived in cities; today the figure is about 50 per cent. Within 50 years, the Chinese will live in one all embracing megalopolis, with every architect able to tap a computer keyboard having built at least 100 towers. Of the lectures so far in the RCA's excellent series, this was the biggest "disturbanism" of them alln