In my fifteen years in Aberdeen, the Old Aberdeen mosque went from a tiny to a flourishing enterprise, with Muslim men overflowing the building onto the surrounding streets. Between 1995 and 2010 in northeast Scotland, the sight of women in burqas and niqabs went from rare to commonplace. The number of ethnic supermarkets serving halal lamb and venison quadrupled. Notably, some of the women clustering with their prams round the Old Aberdeen mosque were evidently not immigrants or from immigrant families. Islam is on the rise in Britain, both by the influx of immigrants and, increasingly, through the winning of converts.

A recent Pew Forum report estimated that the number of British Muslims has almost doubled in the last decade, from 1.6 million in 2001 to 2.9 million today. One study estimated that five thousand Britons a year choose to become Muslim. Why, asks the journalist Melanie McDonagh in The Spectator , “is it that young folk revolted by contemporary excess don’t simply make for the local CofE or Catholic church and rediscover the religion of their grandmothers, rather than getting their spirituality via Islam?” Her answer is robustly Chestertonian: “It is the notion that what exists abroad, or what is foreign to your own background, is somehow superior to what you’ve grown up with, what’s under your nose.”

Attraction to what once would have been called Oriental religion, Chesterton insisted, comes not from an excess, but from a failure of imagination. It takes real imagination, he asserted, to see the homely and familiar, or what our grandmothers taught us, as redolent with wondrous, religious appeal. That was true of those of Chesterton’s contemporaries who went for “Madame Blavatsky religion,” pseudo-Buddhism, and the cornucopia of fake orientalisms generated by the British Raj.

This attraction to the exotic was found even in the Victorian working class. Stationed in Palestine during the First World War, my grandfather was so bowled over by the sight of hooded and kaftaned Middle Eastern men that he lost his Christian faith. This eighteen-year-old boy thought anyone who swirled out of the desert dressed like that claiming to be the Son of God could easily, and mistakenly, have been believed. Like many Englishmen of his time and class he owned a copy of T. E. Lawrence’s Seven Pillars of Wisdom . His love for the Orient was a typically distant one: He left English soil twice, once for what he called “the Great War” and again in the 1970s, when he embarrassed his daughter by telling each French waitress he met, in English, about the circumstances of his previous visit to their country.

Today no British person could encounter Islam as such exotic souvenir territory. The curry takeaway, with its Muslim proprietor, is precisely what is under their nose. The Old Aberdonian Scots who wait patiently, and always respectfully, for business to resume in The Khyber Pass, once the owners have finished eating for the first time that day, know much more about Ramadan than they do about Lent.

Twenty minutes away from genteel Old Aberdeen, with its medieval university, mosque, and Khyber Pass, lies Tillydrone, a drug-infested working-class district. I spent time there last summer, searching for a delinquent cat. Its only public building that I did not tack with a “reward” photo of Pius, was the local church, since it was always locked. If it had been Episcopalian or Catholic, rather than Church of Scotland, it would likewise have been locked against vandals. The mosque in Old Aberdeen is locked, too, out of hours.

Walking between the two communities made me think that if I was a working-class teenage girl with any sense, I’d consider picking a mate from the boys outside the mosque. There are decent people in Tillydrone, and families, one of which returned the miscreant animal. But they receive no apparent moral sustenance from corporate religion. Even wearing a burqa might be a small price to pay for religious leaders who insist the males take on the responsibility of being breadwinners.

Churches look like places where weddings happen, but not where marriages hold together. Those burqaed women with their prams are an obvious expression of the culture of the mosque. The churches don’t feel like communities in the same way. McDonagh notes that “many girls who convert to Islam do so because their boyfriends/future husbands are Muslims.” She doesn’t ask why they chose Muslims as boyfriends, and the “appeal of the exotic” doesn’t speak to the question in contemporary Britain.

Unlike the Ramadan-observant Muslims, Catholics replaced their socially binding meatless Fridays and Lents with amorphous good intentions about “giving something up.” So-called “intentional Christianity” has a middle-class, intellectual appeal, but adopting it has cost the churches the working class. I was reminded of this while looking with an Irish Dominican friend at a magazine photo of thousands of Muslim at prayer. He commented that we had lost the habit of repetitive prayer. The rosary, he said, is how less-educated people like to pray. McDonagh notes that many of the new Muslims in London are West Indian youths, “for whom Islam offers greater discipline and certainty than the Pentecostalism of their parents.”

She doesn’t ask whether that applies equally to the current practice of Catholicism and Anglicanism. Ramadan might make more sense to the literal-minded than giving something up. When I told an Indian shopkeeper I was buying his beans for a vegetarian Friday dinner-party, he said, “Very few Christians here keep their faith.” That might not be true, but it is true that Christian practices are less tangible than Islamic ones. And so the recent decision of the Catholic bishops of England and Wales to bring back the traditional Friday fast presents an evangelistic opportunity. For the Friday fast, like Ramadan and similar disciplines, carries its own visible apologetic.

To a Christian not much more knowledgeable about it than Chesterton was, Islam seems like the perfect “political religion””almost, one could say, the perfect “Marxist” religion. A system of rewards and punishments in the afterlife correlates with a highly moralized and cohesive system of social organization on earth. Everyone knows, and some will even acknowledge, that British Islam also has a much darker side. Former home secretary Jack Straw’s recent observation, corroborated by interviews on a Radio 4 program, that many Pakistani boys see English girls as “easy meat” shows us what it is. That sensible teenager who selects a Muslim mate had better know that an imam who encourages boys to marry and reproduce will discreetly avert his gaze when the husband mistreats his wife. Just “imitating Islam” is not an answer to Christianity’s current failures in Europe.

If British Christianity ever regains the habits it once had, of specified culinary abstinence, repetitive prayer, and chaste fertility, it won’t be in imitation of Islam, but it might be as a recovery of its own originally “Oriental” element. Outside of the imams, Islam has no clerical hierarchy. The horizontality of its communal prayer is a precise visual expression of the core concept of brotherhood in Islam.

Christians fast together in recognition of their solidarity in the body of the crucified Christ. This understanding of solidarity is, if anything, more Oriental than the more straightforward Muslim conception of brotherhood, which seems by comparison rather “Latin” and rational. Christian repetitive prayer, like the rosary, is a means of mental absorption in the historical mysteries of the life of Christ. It’s like yoga, but more eastern than that.

Likewise, the Christian, Pauline image of marriage, in which a man and wife become “one body” like the body of Christ, smacks of the Arabian Nights , in contrast to the more legal conception of marriage, which legitimates divorce within Islam. Or perhaps that is just my grandfather talking, about how Christianity could make converts in Britain today.

Francesca Aran Murphy is professor of theology at the University of Notre Dame and the editor of Theology, University, Humanities (Cascade) .