Sony Ericsson doesn't give a Walkman badge to just any old MP3-playing phone. After all most mobiles have some form of onboard media player. A Walkman phone must go further, offering a package and acoustic experience that is designed for those that take their music on the move seriously.

The W710i meets the audio challenge by coming supplied with half a gigabyte of storage, external controls, and a seriously sensible set of headphones. But it also takes up a new challenge: how to provide a great musical experience to joggers, other sporty types and health fanatics.

This is a phone that is not just built to appeal to those on the move - it actually aims to give you a helping hand with your fitness regime. Runners and walkers will be particularly impressed with the built-in pedometer, which provides you with a wealth of data for you to pore over during and after your training.

This is not a particularly small clamshell phone, weighing in on the wrong side of 100g. And its striking design will be a turn off for some. A strange mixture of shiny plastic and rubber-like panels and trim give it a look to go with the latest sneakers. It is available in two different colour schemes.

The phone looks reasonably robust but Sony Ericsson hasn't gone to the max and provided the weatherproofing and shock-protection that some previous phones designed for active lifestyles have provided. There are nice touches, however.

There is a simple switch on the side to lock external keys - ideal for when carrying around in a pocket, and a locking catch that holds the battery cover in place. The supplied headset has loops that are designed to stop the earbuds from falling out as you pound the streets, making it one of the more comfortable stereo sets to come supplied with any mobile phone.

But as no headset is perfect for everyone, there is provision to plug in your own cans. The supplied handsfree kit is in two pieces, the first half connects to the multipin terminal on the phone (acting as an aerial for the onboard FM tuner), and provides a standard 3.5mm jack connector. The handset also supports the necessary Bluetooth protocols to enable the latest wireless stereo headphones to be used.

The rubber panels at the side of the external screen provide full MP3 track control with fast forward, rewind and play buttons falling easy to hand. The LCD is large, so that it is easy to read the track details without needing to open the phone. However, this passive display is a limited monochrome affair, which shows orange text on a black background.

Opening up the flip you get a full-colour screen, although the quality of the small 220x176-pixel display is not particularly impressive. The camera viewfinder and video playback only occupy part of the available space.

The onboard camera is a 2-megapixel device but unlike on some other Sony Ericsson phones there are no autofocus or close focusing facilities. Picture performance turns out to be a mixed bag. Colour balance and fidelity is excellent, providing a very realistic picture, and without noticeable artefacts.

However, noise seems to be an issue even when light is not particularly dingy. Exposure is reasonable, and avoids the burnt out highlights that mar so many cameraphones but an erratic attitude to contrast means that some images end up looking rather milky.