As the world prepares to mark the fifth anniversary of the 9/11 attacks, journalist Peter Taylor presents the first of two films in which he examines the battle against al-Qaeda. He looks at how war in Iraq has served as a rallying call for disaffected Muslim youth in communities all over the world. He argues that al-Qaeda's demands are not about the desire to revive the medieval caliphate, but are really about United States foreign policy in the Middle East and travels to America to ask the taboo question: is it time to enter into a dialogue with terrorists?
Series producer Paul Jenkins : Executive producer Fiona Stourton 9/11: the Twin Towers is on Thursday at 9pm on BBC1