What Car? guide to portable sat-nav - TomTom One Europe

Cost £269
For A good size with plenty of functions
Against Temperamental when it loses its signal
Verdict A good buy, especially with the downloads

The TomTom One Europe is small enough to carry in your pocket and for practical purposes it is one of the best in this test.

Touchscreen activation means it's easy to operate and easy to understand, offering full postcode navigation. However, during our test the unit was rather temperamental, particularly when it lost its link to the satellites. When it 'found' them again it was unable to continue navigating, requiring a little bit of fiddling.

Pay around £30 (depending on service level) and you can get TomTom Plus, which offers real-time traffic and weather information.