While Isil charges zakat, the alms payment in Islam – essentially an income tax – to those residents who can afford it, Ammar said businesses were protected from theft and corruption.

“When I take chickens that I have bought from farmers in the rural areas to Raqqa the first thing I have to do is go to the zakat office and pay the standard 2.5 per cent.
They then give me a voucher that allows me to sell the produce in the city.”
The model is being applied across Isil territory in Syria, and to such a degree that businesses are now choosing to move their industry into Isil areas.

The owners of factories in Sheikh Najjar, an industrial estate north of Aleppo city, and now a front line, have moved to Isil-controlled Minbij, several residents and business owners told the Telegraph.

“You can find everything from cotton to iron and plastics being processed here,” said one factory owner speaking by phone.