Few outsiders took much notice of the bookshop whose shabby frontage and fading paint blended seamlessly into the rundown Leeds suburb. They were not to know that behind its door lay an incubating chamber breeding believers in a virulent jihadist ideology that one day would bring mass murder to London. The shop on Beeston Hill was called Iqra, Arabic for “recite”. It was the first word of the Koran as revealed to the Prophet. When the shop was opened in 2000 by “a dedicated core of brothers and sisters who have taken it upon themselves to propagate the message of...