By Richard Tomlinson

(FORTUNE, June 12) -- So does Internet grocery shopping actually work? Judging from this writer's experience, there are bugs in the food supply chain. My plan was to order food for a dinner party from the big British supermarkets that offer an online service in London--Sainsbury, Asda, and Tesco. Trouble began when I clicked on Sainsbury's Web site and discovered that Britain's No. 2 food retailer doesn't yet deliver Internet orders in my area. One down, two to go.

Next I loaded Asda's CD-ROM, which is the only way to buy groceries online at the Wal-Mart subsidiary (an "interactive" Web site is promised this summer). The shopping display was simple and well organized, although the range of goods was limited. Ice cream, for example, wasn't available, presumably because the vans don't have freezer compartments. It wasn't until I went to check out that I hit a wall. The CD-ROM was out of date, and Asda's helpful call center informed me that the new version wouldn't be issued for another two days. That left only one option--staring at a computer screen for 40 minutes while the Asda database downloaded the latest price and product information.

Tesco, the world's self-styled leading online grocer, could surely perform better. Er, no. The main problem wasn't the Web site's fussy design or the absence, once again, of ice cream. It was that when I tried to order, a message flashed on the screen informing me that I had committed a "URL protocol error." So it seemed logical to return to the previous page, only to find that the entire order had been wiped from the system. I then called a rather blase man on Tesco's help line, who assured me that my order had been registered and that such glitches "can happen even when the transaction is successful."

Two mornings later Asda's home-delivery van turned up, five minutes before my chosen two-hour delivery slot. (Asda promises next-day delivery. The charge is $5.60, and the store accepts all major credit and debit cards.) The deliverywoman, dressed in Asda's green uniform, was a corporate ambassador straight out of Sam Walton's dreams. She insisted on carrying all the goods up to my third-floor apartment, was enthusiastic about shopping at Asda ("It's so cheap, but you mustn't think I'm paid to say these things"), and even admired the house. Of 22 items ordered, 20 arrived. Unfortunately, the two missing were essential: chicken and potatoes. "Some items can drift in and out of stock," said Asda's ever-courteous call center. Well, yes--but chicken and potatoes?

An hour later a young man in a sweater and jeans rang the doorbell. He turned out to be Tesco's deliveryman, but unlike the Asda woman, he clearly didn't see promoting the service as part of his duty. Of 20 items, four were unavailable. Uncle Ben's long-grain rice was out of stock, so Tesco, as I'd requested, substituted the same company's boil-in-the-bag product. ("A friend of mine eats that stuff," the Tesco man said dismissively. "He's got no taste." Thanks.) The pita bread I wanted also didn't arrive, and no substitutions were provided. Happily, the Greek olives did make it, though as my receipt told the tale, it was a near thing. They had had to overrule an evidently flummoxed store picker, who had tried to substitute unsalted Danish butter. Tesco's service is more expensive than Asda's, charging $8, and it aims for, but does not guarantee, next-day delivery.

My next call? I headed down the road to Safeway--the only one of Britain's big four supermarkets without a home-delivery service--to scare up some chicken.