$5.4bn

Its road network stretches for nearly 7000km, the government’s credit rating is the highest on the continent and per capita income has risen 13-fold to $7 000 (R96 000) thanks to growth averaging 8.2 percent a year, according to the World Bank. Over the past half century, only South Korea and China boast such dramatic increases in national wealth.

“I compare it to an ant and an elephant,” President Ian Khama, the son of founding father Seretse Khama and his British wife, Ruth, told Reuters in his wood-panelled offices in the heart of Gaborone’s bustling government district.

Outside his window, labourers hammered away near high-rise apartment and office blocks more akin to Dubai than the sleepy town romanticised in British author Alexander McCall Smith’s tales of Ma Ramotswe and her “No. 1 Ladies’ Detective Agency”.

“It’s chalk and cheese when you compare what the country looked like back then to what it is now,” Khama said.

To mark the 50-year milestone, state workers festooned streetlights with flags and daubed road- side rocks with sky-blue paint, Botswana’s national colour.

But the celebrations are tinged with unease.

The cornerstone of Botswana’s success has been one commodity, diamonds, and a rigid adherence to prudent use of their revenues, a rarity on a continent where natural riches are routinely squandered, or the cause of civil war. The country’s soverign wealth fund

Besides roads, they have funded hospitals, schools and a welfare state that provides free health care and education to all, generous by African standards.

There is also a $5.4 billion sovereign wealth fund and $8bn in central bank reserves.

But each of Botswana’s 2.3 million people knows that, unlike in the movies, the gems do not last forever, and the breakneck growth they have fuelled in the past will not be repeated.

Even if output remained constant, with a growing and ageing population – life expectancy has risen to 64 despite one of the world’s worst HIV/Aids epidemics – the net effect is a per capita windfall that shrinks a fraction each year. Diamond mining “In a sense, we are eating diamonds,” Econsult Botswana economist Keith Jefferis said. “There is no immediate threat to Botswana’s… ‘business model’ but diamond mining is unlikely to provide economic growth in the future.”

The government has achieved some success in its attempts to wean the economy off diamonds.

Mining made up just one fifth of gross domestic product (GDP) last year compared with half in the late 1980s at the height of the diamond boom, while financial services and tourism – the Okavango Delta is one Africa’s