An editor of mine at The Economist used to reminisce that when Iran was pitched into revolution in 1979, ‘we were caught on the hop by this cataclysmic event in the Muslim world. There was a general ignorance of Islam; you had leader writers frantically trying to find out the difference between a Shia and a Sunni.’ The autodidacts have had much catching up to do since then, as the Western and Muslim worlds have further collapsed into each other – through Muslim communities expanding in our towns; through the spread of ideas facilitated by the Internet; and, most painfully, through war. 

Many non-Muslims in Britain now have a handle on the Sunni–Shia divide, even if this sometimes rests on shaky analogies with Christianity. (Accordingly, the Shias are cast as Protestants and the Sunnis as Catholics, except in discussing the prominence