The Interactive Media in Retail Group (IMRG) predicts that online shopping in the UK will grow to £17bn this year, and customers will expect an increasingly high level of service and choice from the sites they use. Online retailers should therefore ensure that their systems will be able to cope with the increased traffic and raised expectations, or they will lose out to more nimble rivals.

In its annual statement, released in March, the IMRG predicts that this year internet shopping services will substantially improve in both range and quality, and many companies that have not yet used this sales channel will do so.

The group, which represents a number of online sellers, forecasts that 20 million UK shoppers will spend a total of £17bn online this year. Looking further ahead, the IMRG estimates that by 2009 a quarter of all UK shopping will be carried out online or via mobile devices, boosting annual online sales to £80bn.

In the short term, the IMRG said that sales gains would come from increased consumer confidence brought about by secure payment systems offered by credit card giants Visa and Mastercard. The increased use of broadband and safety kitemarks, such as the Isis brand backed by industry and government, will also encourage e-shoppers.

According to figures released last month by Visa, shoppers in the UK are almost doubling their online spending year-on-year. Online UK sales for the final quarter of 2003 were 91 percent higher than sales in the same period in 2002. During the period, Visa cardholders in the UK spent over £1.8bn via the internet.

The IMRG warned that unless web sites meet the high expectations of users they might not benefit from the increased spending. "Those whose services are deficient will find themselves shunned by shoppers and business partners alike," it said.

According to separate research, many retail sites are falling short. The Customer Respect Group's Customer Respect Index (CRI) uses research from online performance software specialist WebAbacus and Aqute Research to rank FTSE 100 companies in terms of how well they respond to customers. The CRI has revealed that although more than 10 percent of all transactions start online, one in five is abandoned due to an unsatisfactory experience with web sites.

The Customer Respect Group noted that many companies are failing to provide contact information. It said that just 34 percent provide an email address for queries, only 10 percent provide phone numbers or postcodes, and 21 percent of companies did not reply to online queries at all. The research found that unless shoppers receive a response within one business day, two-thirds look elsewhere.

The IMRG members said the development of customer retention strategies was their highest priority. Dan Drury, chief executive of WebAbacus, said service levels need to improve: "Even when the internet gave companies a whole new way of treating customers, UK companies have still managed to let customers down."