Tesco comes out top in mobile web site speed test

The mobile web sites of Tesco, Next, Marks & Spencer and John Lewis outperformed their peers across five countries in terms of download speed, according to a recent survey from cloud monitoring firm Keynote Systems.

All boasted download speeds of less than seven seconds, with Tesco's mobile site being the fastest with an average download time of 4.39 seconds.

Robert Castley, lead solutions consultant at Keynote Systems, explained that the high-performing sites each have one attribute in common: they have optimised their sites for mobile devices.

"They are detecting the browser type connecting to the web site, based on what's called the user agent stream, so they can determine what kind of device that is," he said.

He explained that the sites are able to verify the type of device being used and which browser it is accessing the site from, be it iOS, Android, BlackBerry or any other.

"Because they're able to detect who you are and what device you are on, they immediately start serving up the site that has been optimised for that particular platform."

He added that the download speed could have a direct impact on the firm's revenue, if they are providing revenue-based transactions for handheld devices. There are also customer loyalty and customer abandonment issues to consider, added Castley.

"If I'm in town and hit a mobile site through Google and its really slow and not performing, then I'll go back to Google and choose the next option on the search list," he said.

"So you could get user abandonment, and users not even waiting to access the site if it's particularly slow and it's important for firms to know how many users they're losing due to slow performance."