Murder in Woolwich: was this gruesome beheading the work of serious jihadis or demented young men using Islam as an excuse for their psychotic fantasies? And will we see more incidents like this as religious extremism – and an anti-Muslim backlash – grows in our cities? This week's Telegram offers expert commentary from Shashank Joshi, one of the world's leading authorities on Islamic terrorism, our chief political commentator Peter Oborne, and Sunday Telegraph columnist Janet Daley.