Kotiogo Ng’usilo vividly remembers the first time he saw a car. It was the 1950s and Mr Ng’usilo, a hunter-gatherer from the Ogiek tribe in Kenya’s Mau forest, thought it was a “moving house”.

These days, at 86, though he still tries to preserve a hunter-gatherer lifestyle, foraging for honey and secretly bagging the odd hyrax, he has moved with the times. He wears western clothes, buys food at the market and, like his younger relatives, uses a mobile phone. His story about the old days — which he recounts over sacred honey beer — is interrupted by incessant chirruping, not from birds but handsets bringing news to the forest from the city.

The rapid spread of mobile technology in the developing world — especially in Africa, which has lagged behind most of Asia and Latin America in closing the income gap with the west — has given rise to the theory of “leapfrogging”. This has it that, in the words of a World Bank study, countries can make “a quick jump in economic development” by harnessing technological innovation.