A lengthy New Statesman article by ICSR's Shiraz Maher:
From Portsmouth to Kobane: the British jihadis fighting for Isis

(Sub-title) What motivates the young men who leave Britain to join the murderous fanatics of Isis in the Middle East? Shiraz Maher spoke to dozens of them inside Syria to find out.
Link:http://www.newstatesman.com/2014/10/portsmouth-kobane

The stories of the Portsmouth and Manchester boys offer a remarkable insight into the world of foreign fighters in Syria and Iraq. They also reveal the deep chasms within British society. Second- and third-generation immigrants of Muslim Asian origin continue to feel a profound detachment not just from the country in which they were born and educated but from their own families and communities, too. Many of their local leaders are too old to counter the charisma of millenarian propaganda and their experiences are too remote from those of their congregants.

Their stories remind us how powerful social media can be.