IBM ThinkPad X31 TK1C8UK

Usually, having an ultra portable on the train results in people stealing a second glance at the snazzy item on your lap, but the X31 won't even get a single glance. IBM has stuck with the black, square-jawed look that has defined its ThinkPads since they were first introduced in the Stone Age - it's just that little bit smaller. But the X31 isn't built for people who want others to notice how rich or stylish they are. It's built for business, so its key features are build quality and portability - and it has both in abundance.

By portability, we aren't only referring to its weight. In fact, 1.65kg could be considered on the heavy side for an ultra portable with just one spindle (there's a hard disk but no optical drive). Portability has got much more to do with battery life, and the X31 lasted for a stunning four hours, 47 minutes in our light-use battery tests - compare that with two hours, seven minutes from the previously A-Listed Dell Latitude X200 (see issue 97, p122).

What's more, if you buy the extra-life battery, which fits snugly underneath the main battery via the docking station port, you could keep using the ThinkPad for around eight hours - it lasted an unmatched nine hours in our tests.

Much of this amazing battery life stems from the Pentium-M processor, the most important aspect of this Centrino machine. This is a huge credit to Intel's designers, as it packs plenty of power when you need it, but draws remarkably little power overall. The X31 comes with the 1.4GHz variant, which was still enough for 1.11 in our 2D benchmarks - 11 per cent faster than a 2GHz Pentium 4 desktop PC.

Another benefit of the Pentium-M is that its packaging is far smaller than the Pentium 4-M, which is one of the reasons why IBM can fit it into such a tiny chassis. The X31 measures just 272mm across and 222mm deep, giving it the footprint of a hardback book. If we have a criticism, it's that it measures 31mm thick, which is 7mm more than the Dell Latitude X200. Still, you're not going to struggle to fit the ThinkPad into a briefcase or bag.

The real marvel, though, is the quality of the keyboard. Despite being narrow, it's easy to type on, with full-width keys in all the most important places - note the huge Enter and spacebar keys. The only omission, as ever with ThinkPads, is a Windows key. IBM has also followed its usual convention of a TrackPoint rather than a touchpad, but this makes sense with the smaller palmrest area.

And the screen offers a similar level of quality. Its contrast is excellent, as is its colour handling. Its only problem is the 12.1in viewable diagonal, which feels small when the sub-2kg Samsung X10 has a 14.1in screen. Nevertheless, the pixels are big enough to be read easily, so you won't be straining your eyes by looking at the X31 for hours.

IBM has also taken care to protect the screen with a sturdy lid, and this quality extends to the rest of the ThinkPad. Everything has that reassuring engineered feel that you get from IBM's notebooks, and it's not just a feeling: IBM won the PC Pro reader-voted Notebook Reliability Award last year, with only 2 per cent of readers considering their IBM notebooks to be unreliable. No other manufacturer could even beat the 5 per cent mark.

IBM also scooped the Service Award, and there's plenty of support built into the X31. This mainly stems from the blue Access IBM button above the keyboard, which covers a huge range of areas: Learn gives you a comprehensive and easy-to-follow guide to the X31's features; Configure lets you take control of power management and connections; and Protect & Recover helps you secure data and back up the system.