It seems retailers are suffering from an extended New Year's Eve hangover.

Our latest quarterly online survey shows the high standard of service achieved in September could not be matched this time round, with lengthy delivery times, a host of missing items, invoice errors - and still more plastic bags.

The most impressive performance came from Asda, delivering all 33 items, which included two well-chosen substitutions. In addition, the Asda website was quickest to navigate and the delivery driver was especially helpful. As a result it replaces Tesco as our winning delivery service.

But delivery times for the shop overall, which took place in the first week back after the Christmas holiday for most consumers, were lengthy.

In September, three of the five retailers could guarantee next-day delivery, but perhaps in an indication of the increased popularity of online shopping, this time around only Ocado could promise such fast service and the soonest Asda, Sainsbury's and Tesco could deliver was three days. However, all five of the deliveries arrived within the specified time slots, which is an improvement from last time.

There were mixed results in terms of availability and substitutions. Asda replaced the 907g Birds Eye frozen peas with an 800g pack and provided a larger bag of McCain oven chips for the 1.5kg bag. Our Ocado shopper was instantly informed the Shreddies and McCain chips would be unavailable by a pop-up screen on the website, which was helpful.

Four items were unavailable from Sainsbury's so alternative sizes of the in-store loaf, Birds Eye peas and sausages were provided as well as an own-label tomato soup for the Heinz variety. However, the rump steak was out of stock and our shopper was told no alternative could be found, which - for a popular cut of meat - was odd.

The Shreddies, frozen peas and McCain chips were not ordered by our Tesco shopper as they were not available on the website, so she was expecting three fewer items. The wholemeal loaf was not delivered as it was out of stock, but our Tesco shopper was disappointed to receive no substitute.

Our Waitrose shopper received organic versions of the orange juice, tomato soup and milk without explanation but she could hardly complain as they were billed at no extra cost, while the rump steak was replaced by a more premium Hereford extra-trimmed version. A substitute for the unavailable Shreddies and in-store loaf could not be found, however.

The accuracy of receipts has traditionally been a strong area for online retailers but Sainsbury's charged our shopper for 10 packs of sausages, although only the required single pack was delivered.

Sainsbury's has also clearly done nothing to lessen its use of plastic bags, using 18 bags to pack just 32 items, up from 11 bags last time.

But none of the retailers covered themselves in glory on this count as a whopping 54 bags were used in total by the five online retailers, up from 41 in September.

At the time Asda was the worst offender, using 15 bags, but though it managed to reduce the number of plastic bags it used in the delivery to 12, it still used twice as many as Tesco, while Tesco's seemingly spendthrift six bags for 29 items constituted more bags for fewer items than the four it employed last time. Waitrose and Ocado also used more bags for fewer items and the drivers for these deliveries, as well as Tesco, did not offer to collect them for recycling.

The courteous and helpful nature of the delivery drivers has always been a positive element of the online deliveries and this time was no different. Asda's driver remained cheerful and polite as he carried the 12 bags up four flights of stairs and the other drivers also impressed with their efficiency. Tesco's driver was especially helpful as he managed to fix a smoke alarm, which had been beeping for hours.

But customer service is only part of the online delivery experience and retailers must reduce the number of bags used or risk disillusioning an increasingly environmentally aware customer base.