The unrest was sparked when a woman in niqab was ordered by police to reveal her face. She refused, allegedly assaulting a police officer. Belkacem, whose group is based in Antwerp, posted a video online advising Muslims to use violent means of protest, which prosecutors allege intended to inspire hatred and violence.

Whether the courts agrees still has to be determined, but Belkacem has now been required to serve a sentence he was handed last year for the same kind of offence. Because of the overcrowded state of jails in Belgium, it is rare for anyone sentenced to less than three years to go to jail, but in this case an exception can be made, federal justice minister Annemie Turtelboom said after talks with the Brussels prosecutor.

Meanwhile, federal interior minister Joëlle Milquet is considering whether to introduce a law to ban organisations like Sharia4Belgium that advocate the use of violence and whether to withdraw Belkacem’s Belgian nationality. Other politicians point out that Sharia4Belgium is not an official organisation, so it would be impossible to ban and that its members – estimated at no more than about 70 – would simply gather under another name.

Other Muslim groups distance themselves from Sharia4Belgium, but are opposed to revoking Belkacem’s nationality, as they say it would send the wrong signal to other naturalised immigrants.