The consequences for online retailers whose websites suffer poor performance could be grim in terms of sales returns, according to a new study from JupiterResearch.

Online shoppers cited a malfunctioning or slow-to-respond site as the number-two reason why they would not make a particular online purchase, behind only overly-high prices in the list of consumer complaints.

Taking into account the responses of over a thousand people who shop over the internet, the JupiterResearch survey found that the average online consumer will now wait no longer than four seconds for a site to load before giving up.

Vice president of marketing at Akamai Technologies, which made the study available, said: "The critical takeaway from this research is that online shoppers not only demand quality site performance, they expect it."

"Site performance becomes even more critical as retailers add more dynamic content and applications to their site," he added.

A recent study by the British Council of Shopping Centres concluded that the growth in online retailing is likely to be driven by men who want to avoid the high street and not women looking for some retail therapy.