A short video (12 mins) about five boys - three of them brothers - who left Brighton (UK) to Syria:
Mark Townsend asks why....... to join an al-Qaida affiliated group. What clues were missed? What was it about them that should have alerted the authorities to their potential radicalisation?
Link:http://www.theguardian.com/world/vid...to-syria-video

There is a longer written "long read". On a first glance I do wonder if this is actually true:
Their journey from the south coast to Syria cannot be reduced to a single factor, but it involves racist abuse, allegations of police neglect, and the collective failure of numerous authorities – both those charged with protecting vulnerable young people, and those charged with preventing radicalisation.
Link:http://www.theguardian.com/uk-news/2...to-jihad-syria

What about the factors that persuaded them to go? Brighton can in places be wealthy and has a strong gay community - which may be a factor, not mentioned in the article.