The Christmas shopping period was believed to have been the busiest ever for online retailers and, in the build up, the press was full of scare stories about lack of delivery slots and the supermarkets having to turn customers away.

The reason for this, of course, said the retailers, was to ensure normal service and availability standards were maintained, as well as allowing stores to cope with the extra shopper numbers at this time of year.

So how did they actually perform? Across the board our shoppers had no problems getting delivery slots for Saturday, December 17, the penultimate Saturday before Christmas, and most reported plenty of slots available in the days running up to Christmas. However, availability and service did slip from previous online orders.

Only Sainsbury and Ocado delivered the list exactly as ordered by our shoppers without substitutions, while our shoppers at Tesco, Sainsbury and Waitrose all had complaints about the service level received in terms of either the delivery itself or after-care service.

The most improved online retailer on this occasion was Asda, following disappointing performances in the two previous online surveys through poor availability and unsuitable substitutions.

This time our shopper had no complaints. He found the site easy to use and said that the ordering process was clear and simple to use. Availability was not what it could have been, with three out-of-stock products resulting in substitutions.

However, the substitutions were all logical and, in fact, ended up saving our shopper money. The own label double cream was switched with a branded line, while he was only charged for the cheaper own label items. This was also the case with the tomato puree that he ordered.

The 400g pack of own label prawns was swapped for a cheaper 300g pack with a 50% extra free offer, giving him more than he had ordered for a lower price. Our shopper was also impressed by the delivery driver, whom he said was able to answer all his questions.

Online specialist Ocado proved that it had not compromised in terms of service. The retailer sold only 30 of the products on our list but provided them on time exactly as our shopper had ordered.

She said the ordering process was smooth and also praised both the driver and the quality of the fresh products that she received.

Tesco had picked up our Star Order award for each of the past two surveys but failed to complete this order to our shopper’s satisfaction. Having ordered 32 items - as Kingsmill crumpets were not sold - she received two substitute items. She was given two 200g packs of prawns to make up for the missing 400g bag, which was fine, but received a lower quality tub of ice cream than ordered.

In terms of the order Sainsbury did well, delivering 32 items without substitutions. However, having given our shopper a two-hour delivery slot, the order arrived half an hour early. Our shopper was just returning home at the time and was fortunate to catch the driver, who was heading back to his van.

Our Waitrose shopper was also unhappy with her delivery. Again there were two substitutions, with one acceptable and one not. Prawns caused a problem again as she received one 200g pack instead of the 400g format she had asked for.

She also said that the order was poorly packed, which resulted in the Cornish pasty being crushed by a heavy tub of ice cream.