Business English: BlackBerrys are the only fruit in the malls of Lagos

A man in a shiny white suit spots a pretty woman wearing a cocktail dress and high heels. "Hello beautiful," he says. "My name is Duke. What's yours?" She ignores the question and shows him the four BlackBerry mobile phones in her hand. To gain her interest, he would have to buy her a newer model, a Bold 3, "with a full-year internet subscription", she tells him. "Then, only then, can you actually, really, talk to me."

It's a scene from BlackBerry Babes, a popular movie released by Nigeria's prolific film industry last year. Like most "Nollywood" features, it is low-budget, over-the-top and often hilarious. But the basic premise - that Nigerians are obsessed with BlackBerrys, both as status symbols and communication tools - holds true.

While sales of BlackBerry's smartphones decline in the US and western Europe, they are climbing fast in emerging market regions such as Africa, where, from a very low base, the middle class is growing.

  A Blackberry smartphone

There are more than 620m active mobile lines in Africa, according to the GSM Association, second only to Asia. Nigeria, the continent's most populous nation with 168m people and an increasingly important destination for multinational companies, accounts for nearly 100m active simcards. About one in 20 is in a smartphone.

Research in Motion, which makes the BlackBerry, says the west African country is "one of our fastest-growing markets". Though RIM does not divulge sales figures, Informa Telecoms and Media reckons that BlackBerry accounts for 20-30 per cent of the 5m smartphones in Nigeria - between 1m and 1.5m handsets. Mobility, a Lagos-based telecoms consultancy, estimates the number of BlackBerrys here may be closer to 2m.

Sales in other African countries have been strong, including South Africa, Kenya, Ghana and Tanzania, RIM says, though the high market share in Nigeria appears to be unique. "There has been the perception that people in Africa would want a cheap smartphone, but that's not what we've found," says Waldi Wepener, RIM regional director for east, west and central Africa. "Nigeria has a burgeoning middle class."

That is true, though the picture is not clear. The rate of poverty in Nigeria increased from 55 per cent to 62 per cent from 2004 to 2011, according to a recent government report. But because the population grew at a higher rate, the total number of Nigerians who can be considered lower middle class or above jumped 7m to 64m.

It is the more affluent members of this group who, in cities such as Lagos, are filling malls featuring South African supermarkets, KFC outlets and, of course, shops owned by Nigeria's four main mobile networks, which all offer BlackBerry packages. None of them has a partnership with Apple to sell iPhones, mainly because of problems when local credit cards are used to register with the iTunes service.

When RIM entered the market in 2006, its handsets were used mainly by high-flying executives. Status is important in Nigeria society, and the device quickly became an aspirational brand, like the sportscars outside the new Porsche dealership in Lagos, or the Moët champagne on the menu in restaurants. Some people who bought BlackBerrys never subscribed to the service; it was enough to be seen with the smartphone.

But during the past six years, as the number of mobile subscriptions has trebled, the telecoms market has changed. While the first mobiles gave Nigerians who had never had fixed lines the chance to communicate over distance, faster networks and smartphones have given people who cannot afford computers access to the internet, and social media sites in particular.

"People have stopped going to cyber cafes, since they can use their phones to do the same job," says Yomi Adegboye, managing director of Mobility. Today BlackBerry in Nigeria is less about business, and more about youth culture, he adds. Indeed, the typical customer is likely to be a young graduate or student. Divine Amarachi, 26, bought hers to help with a degree in peace and reconciliation studies, which she is doing by correspondence. "I do research and file all my assignments using my phone," she says.

The likes of Samsung and Nokia have strong presences in Nigeria, and are promoting their smartphones. But Thécla Mbongue, senior research analyst at Informa, says it is the Android smartphones from Chinese handset-makers, sold by the local mobile networks for about USD120, that are more likely to eat away at RIM's market share.

For now its position appears safe, with BlackBerry sales spurred by falling costs. The entry-level handset now sells for less than USD200. Monthly subscriptions have dropped from USD25 to less than USD10 in the past year. You can even subscribe on a daily basis for about USD0.65.

Customers have learnt how to make their money go far. Tochi Eze, 30, an accountant, makes voice calls only to her parents. Everyone else she chats with using BBM, BlackBerry's free messenger service. She buys shoes and hair from vendors who post their wares on the service, and pays using internet banking - on her phone. Her monthly bill comes to less than USD20. "For me, my phone is not just hype or a class thing," she says. "It's a necessity."