Copilot differs from most satellite-navigation systems in that it's designed to be installed on a mobile phone or handheld computer, rather than as a standalone device.

That might sound like hard work, and more unwieldy than simply buying a ready-to-go device, but the idea is a good one for those who already have a decent, reasonably powerful phone.

With the decreasing cost of such phones, more and more of us fall into that category, and several phone manufacturers are now building GPS receivers into their phones. Nokia is one, with its N95, and O2's XDA Orbit – on which we looked at Copilot – features the same technology.

Of course, this means that screen quality, the method of operation and to a certain extent the ease of use will depend on what phone you choose. The software works in the same way to a standalone navigator once it's installed, and voice directions are clear, although on our test phone they weren't very loud even at the high volume setting.

The software was a bit slow to respond to button presses and, similarly, took a relatively long time to calculate routes. However, once in motion, it was able to quickly recalculate routes with few problems (when we took a wrong turning, for instance).

The program includes several types of vehicle, so you can tell it you're driving a lorry, and it will avoid small roads. It also has a pedestrian mode as well as a selection of map styles including one where no map is displayed, only a series of driving directions.

In the default 3D and 2D map modes, it was easy to follow the route. However, all of the options are stored away in the menus, and getting to any of them means a lot of button pressing.

Copilot Live 7, for Windows Mobile phones, costs £84, or it can be bought wit h a GPS receiver or with a phone from various networks (it's free, with the XDA Orbit, from O2 if you sign up to a £35 per month contract).

Vista compatible: N/A