From at least 1870, British diplomacy tried to shift the centre of gravity in global Islam from the Turks to the Arabs. The Dutch tried to stop their Muslim subjects deferring to the caliph in their public prayers. With somewhat more success, the French promoted alternative centres of spiritual authority among the Muslims they ruled in Algeria and Morocco. As long as the Ottomans retained control of Libya (ie, until 1912), the caliphate kept some sway in North Africa. But when Turkey's new secular nationalist rulers finally abolished the office of caliph in 1924, their job was made easier by the fact that European powers had been sabotaging the sacred office for decades.
As Mr Laurence sees things, the abolition of the old caliphate created a vacuum that has been filled, over the subsequent century, by much darker substitutes, up to and including the new caliphate proclaimed by Abu Bakr al-Baghdadi, the leader of Islamic State. Even where they stop short of fomenting anti-Western violence, global networks of religious fundamentalism and puritanism, such as those linking preachers from say, Pakistan and Saudi Arabia, have replaced the relatively emollient tone set by the Ottoman caliphs, who were connoisseurs of Western art and music, as a colleague has written.