(Villepinte prison guard Blaise Gangbazo walks on grounds overlooking the prison facilities in Villepinte, April 24, 2013. REUTERS/Jacky Naegelen )

In France, the path to radical Islam often begins with a minor offence that throws a young man into an overcrowded, violent jail and produces a hardened convert ready for jihad.

With the country on heightened security alert since January when French troops began fighting al Qaeda-linked Islamists in Mali, authorities are increasingly worried about home-grown militants emerging from France’s own jails.

But despite government efforts to tackle the problem, conditions behind bars are still turning young Muslims into easy prey for jhadist recruiters, according to guards, prison directors, ex-inmates, chaplains and crime experts interviewed over the last few months by Reuters.

“I have parents who come to me and say: ‘My son went in a dealer and came out a fundamentalist’,” said Hassen Chalghoumi, imam of the mosque in Drancy, a gritty suburb north of Paris.