Any first-time visitor to Africa is faced with a whirl of new experiences, but the awful roads are guaranteed to make an impression. That is true even in many cities – when I visited Douala, the commercial hub of Cameroon, I was appalled to realise that a four-wheel-drive vehicle was all but a necessity.

Cameroon’s roads also made an impression on Robert Guest, author of The Shackled Continent. Guest once hitched a ride on a Cameroonian beer truck travelling the equivalent of London to Newcastle upon Tyne – about 300 miles. The journey, detouring around a collapsed bridge on unpaved rainforest roads, took four days.