Are you old-fashioned enough to remember when people went to cathedrals to pray - or, at least, to admire the architecture? When commercialism was frowned upon and the only hint of it was a stall at the back selling postcards and religious books?

Not any more. Nowadays the church, like everyone else, speaks the language of the marketplace. "Church shops are attractive retail outlets these days, good places to buy presents and not just religious items," says Carolyne Baines, secretary of the Cathedral and Church Shops Association, whose Cathedral Show in Newquay, Cornwall on 6 November is expected to attract 50 trade stands and 100 shop managers. Along with the publishers and the makers of church candles will be companies selling everything from glassware to confectionery.

Confectionery? "We've exhibited at the Cathedral Show for the past three years and seen a growth in business as a result," says Katherine Ebbs of Personalized Products in Hampshire, who supply own-label chocolates to Norwich, Winchester and St Paul's among others. "All tourist facilities, including cathedrals, are becoming more aware of the value of gift shops. People want to take something away from their visit and cathedrals need money like everyone else."

But what does chocolate have to do with a cathedral? The answer is that anything will do so long as it has the magic words on the wrapper. Last week I popped into my two local cathedrals to see what was on offer. At Peterborough, one shop sells religious books, another souvenirs. In the latter you can buy Peterborough Cathedral wine for pounds 4.75 a bottle; cut- glass engraved decanters, pounds 100; dusters, oven gloves, T-shirts and tea towels, all bearing the cathedral's picture; or teddy bears, "found at Peterborough Cathedral", for pounds 1.85. There are pencils and key-rings and plastic models of monks. Oh, and CDs of church music as well.

Down the road at Ely, the heritage industry is in full swing - lavender and pot-pourri, shortbread, clotted cream fudge, most of it not even pretending to have an Ely or a church connection. You could easily be in Past Times or a National Trust gift shop. There are things you never knew you needed, like a ceramic bunny dispensing cotton wool (cotton wool not included, pounds 2.90).

Look carefully, though, and you just might find a treat. I picked up a beautifully hand-turned candle-holder, created out of ancient oak salvaged during cathedral restorations, for just pounds 3.95.

Ely, in common with around half of the country's cathedrals, opens its shop on Sundays. The Church of England has no official policy on this, leaving it to the discretion of each individual Dean and Chapter. So Canterbury does, but St Paul's doesn't; Durham doesn't but Southwark does.

Hang on a moment. Isn't the Church supposed to be against Sunday shopping? "Tourists come on Sundays, and want to buy mementoes of their visit," says Canon Dennis Green, Vice Dean at Ely. "We have always opened on Sundays, even before the legislation. You can't impose a Christian ethic on non- Christians who wouldn't understand." Or, as someone else put it to me more bluntly, when Sunday is the most popular day to visit, commercial necessity dictates. In the battle between God and Mammon, it seems, God has his work cut out.