The basement of a middling hotel on the outskirts of Istanbul is a million miles – and a 15-minute taxi ride – from the city’s glittering Bosphorus nightspots. But it is just as busy.

Here, hundreds of people – mostly young men – are dancing to hip hop beats. These are clean-living Muslim boys. They do not drink, and few of them smoke. All raise their hands when Ceza, Turkey’s most popular rapper, walks onstage.