Sales of cellular phones are soaring in South Africa, writes Dominic Cavendish
A woman is pushing a child in a buggy down a leafy Johannesburg side street. One hand is doing the pushing, the other is gripping a mobile phone, into which the woman speaks intently. If it were an advertising image, it would be a cringe-making clich, but this is a black woman filmed unawares. The shot, taken for Channel 4's weekly bulletin programme Africa Express, shows how South Africa has become, unashamedly, the Mecca of the mobile.

"Ringing the Changes", to be screened tomorrow night, looks at the way in which cellphone technology has gone from being the preserve of white yuppies to infiltrating the most deprived black township areas since Nelson Mandela's presidential inauguration last May. "It's revolutionising South Africa," says the presenter, Audrey Brown, "majority rule, majority talks". The statistics, few of which are directly quoted in the piece, seem to bear this out.

There has been an unprecedented growth in demand since the government opened up the airwaves for cellular use last year. There are now around 300,000 subscribers to the two competing digital networks (run by MTN and Vodacom), three times the predicted number for the first year. This can be attributed both to licence requirements that they install at least 22,000 community phones in the townships by 1998 (there are already more than 1,000) and also to the rapid take-up by South Africa's new black entrepreneurs.

Clearly, the government's aim is for a telecommunications infrastructure to be set up as quickly and cheaply as possible, circumventing the heavy investment needed to install fixed land lines. All the inhabited areas of the country are now covered by the networks and it seems that the shift to the townships is as much a strategy for economic growth as a gesture of democratic emergence. Community phone booths - equipped with 10 phones apiece - are being set up overnight in the unlikeliest places, including disused shipping containers on waste ground. It is the first time public payphones have been linked to a digital network.

Ms Brown visits a shanty town where the market has ended up congregating round what looks like a glorified shed. Run by a local businessman under a franchise agreement, its power supply comes from a nearby butcher's shop. Many of the locals, now growing accustomed to recent technological advances such as voice-mail, still have no running water.

Images of the developing world - a horse and cart, for instance - contrast with those of entrepreneurs carting round their mobile wares, but it is not clear how the average black worker can afford the standard 125 Rand monthly charge (nearly a tenth of the average wage).

The phone has long been an emblem of sophistication in fashion shoots or in the photos of black city workers who wanted to impress the folks back home. The mobile is an even greater status symbol, attracting top models. Now dominating the billboards is an image of Charles and Di, separated by a mobile phone company slogan, "We could get just about anyone talking". The digital dog and bone has got a lot to live down to.

The second series of `Africa Express' starts tomorrow at 8.00pm on Channel 4.