Tesco’s online service has blown its rivals out of the water in the latest online Grocer 33 survey. Improved search and navigation on the site sped up the shop, and once again the retailer was the only supermarket to offer an alternative to bags.

But it was service and availability that clinched the deal: Tesco was the only supermarket to deliver the full shopping list with no substitutions or non-deliveries.

Asda, last time’s winner, didn’t fare so well despite a recent overhaul of the site. Our shopper criticised the search facility, saying it made shopping more difficult, and was unable to buy loose produce. The delivery itself was a bigger disappointment as the driver came across as “inefficient and poorly trained”, and arrived at the end of the two-hour slot, not completing the delivery until five minutes after the slot finished.

Service was better at the other three retailers, with Ocado’s driver getting particularly high praise. Our shoppers also appreciated the free gifts from Waitrose and Ocado – cookbooks and The Times, respectively.

Poor availability, particularly at Sainsbury's, let down otherwise strong performances. With regards to plastic bag use, Sainsbury's – which was the worst performer last time – used six fewer bags this shop. Waitrose, however, doubled its number of bags to 14 and didn’t offer to return them to the store once the shopping had been unpacked.
Star order: Tesco, Camarthen, Wales
Tesco easily netted the star order award thanks to solid availability and a friendly, helpful driver who charmed our shopper.

None of this is down to chance, says Tesco Online marketing director Ian Crook. Tesco has put its hundreds of drivers through an Excellent Delivery training course, he says.

"We've been encouraging our drivers to deliver to fridge door, not front door," he explains. "This makes a big difference to customers, especially when we're delivering crates. They've also received more training on customer engagement."

Tesco has also been working on boosting its availability and reducing the number of substitutions - a major gripe for many shoppers.

Staff verify their picks with handheld scanners, and the number of mistakes has fallen as a result of refinements to this system.

If Tesco can sustain its solid availability and service, it will prove a tough titleholder to beat come the next survey.