This article was originally published on August 21, 2016 and updated on September 6 to reflect Choudary's sentencing.

Radicalisation to violence is a deeply personal process. It’s about an individual making a set of choices for their own reasons within a broader political context that leads them to turn against a society into which they were born.

This makes it very difficult to counter and even harder to remove once it has been embraced. Few effective solutions exist, and they are even harder to implement inside a prison.

The jailing of extremist preacher Anjem Choudary – and the prosecution of a number of his acolytes from the now-banned al-Muhajiroun organisation – means the prison system will again be absorbing a new batch of radicals into a population of alienated and sometimes violent young men who are vulnerable to their message.

Managing them will be a complicated process, so the Ministry of Justice has announced a new approach: the “most dangerous” extremist prisoners will be isolated from the general population in special high-security units likened to "prisons within prisons". But will it work?