Three years ago, the Iranian singer and composer Sara Najafi came up with the idea of hosting a concert in Tehran, her hometown. It was a plan so audacious, it seemed slightly nuts. The concert would be “a festival of the female voice” featuring solo singers – not just Iranians, but artists from France and Tunisia, too. Nothing like it had been attempted in Iran for 35 years: after the Islamic Revolution of 1979, women were banned from singing solo in public.

What’s more, Sara was inspired by the Green Movement, which grew out of the mass protests at Iran’s 2009 presidential election result. “It brought me to a new idea of music,” she says. “Basically, I wanted to make music for that movement.” Some choices of performer seem to have been designed to provoke the authorities, not least Emel Mathlouthi, the Tunisian singer whose song Kelmti Horra became a protest anthem during the Arab Spring.