IBM seems to have settled into the same style of product development with much of its notebook range that characterises certain other savvy manufacturers. Oddly enough, the first comparison that springs to mind is Rolex.

This is not as left-field as it might seem. Both companies advance cautiously, making relatively small, incremental changes to tried and tested designs. Both have ended up with a deserved reputation for quality and a number of products which are manifestly superior to much of the competition. Great bursts of creative fireworks might be relatively infrequent, but there's absolutely no doubt that this approach delivers results.

In this case, it has delivered the Thinkpad X30, which for want of a better term, is a sub-notebook. In other words, it's smaller than the vaguely A4 format common to most portables and as a result it's much more suitable for the regular traveller. The 273mm x 223mm (W x D) footprint makes this Thinkpad one of those machines that could, at a pinch, fit inside a briefcase. At 1.65kg, it is also light enough to be carried in this way, so you could potentially dispense with that annoying second piece of cabin luggage; the bulky computer shoulder bag with 'mug me' written across it in neon lettering.

As usual, this combination of size and weight has come at the cost of internal floppy and optical drives. These are available as external units, and as usual, you get to pay extra for them - £49 for the floppy drive and a stern £293 for a DVD/CD-RW combo.

A travelling notebook must be durable, or it will soon die, so we were happy to find that the Thinkpad X30 is largely encased in titanium alloy, including the vital, screen-saving lid surface. Pick it up and you can instantly tell that you are holding a decent piece of workmanship. The machine isn't just tough, it's also well thought out. The core specification makes sense for a portable, general-purpose business machine: 1.2GHz Pentium III-M at the helm (fast enough but not so hot as a P4-M), 256MB of PC133 SDRAM memory and a 40GB hard disk.

If you want to upgrade the memory, there's an empty SODIMM socket readily accessible under a plate in the base. If the hard disk needs to come out for replacement, removing it is the work of a moment.

Some sub-notebooks are a Faustian bargain between size and usability, but not this one. There's enough room for the keyboard to have the right proportions, including sensibly-sized Spacebar and Enter keys. This means you can actually type on it at a reasonable pace, and your hands won't fall of after half an hour. You might prefer a touchpad to the keyboard-stud pointing device IBM is so fond of, but this is the only niggle here.

The screen is as large as it reasonably can be in the circumstances, which gives it a 12.1-inch diagonal. The 1024 x 768 native resolution means small text and screen objects, but most people manage quite happily with this combination. The TFT panel itself is brightly lit, generates vivid colours, and has a reasonably wide range of viewing angles.

Behind the scenes is a somewhat unglamorous but perfectly adequate Intel 830 graphics controller. This is basically part of the motherboard chipset, and like most such integrated GPUs it borrows 16MB of memory from the main system. If we have a gripe here it's really that a machine as expensive as this ought to offer something a bit more sophisticated than i830 and shared memory architecture.

IBM has wisely kitted the Thinkpad X30 out with plenty of ports, so you don't need to carry a docking base around with you everywhere just in case. The line-up includes two USB sockets, FireWire, VGA, a Type II PC Card slot and a CompactFlash memory card slot, plus a parallel port. Comms are provided by the usual combination of an internal 56K modem and 10/100Base-TX LAN adapter, but you also get 802.11b wireless networking, and of course (this being IBM) Bluetooth.

Sub-notebooks need decent battery life or there's no point to them, so the spectacle of the Thinkpad X30 running quite happily for 3.5 hours was just what we were hoping to see. If you are serious about working on the go, you can clap a secondary battery under the base and boost the running time to nearly 7 hours (yes, we did test this). The battery costs an extra £140, and brings the weight up to 2.1kg, but when DC running time is paramount this will prove an acceptable price to pay.

We weren't expecting particularly great things out of the Thinkpad when it came to performance, so we were pleasantly surprised here too. In fact it turned out to be respectably fast for its class, especially considering that smaller notebooks often don't run as fast as their larger counterparts. The final dollop of icing on the cake comes in the form of a generous three year international carry-in warranty, something you should never leave home without.

So do you go out and buy this notebook? Well, yes, if you can afford it. Like a certain brand of wristwatch, the Thinkpad doesn't come cheap at, although the price is only a recommended one and there will be some dealer discounting.

The fact that you have to pay extra for the drives and extra for the neat little docking base (£149, thank you) means that if you want the full package, you are going to have to pay handsomely for it. On the other hand, the same rules apply everywhere - if you want something demonstrably superior, you are going to have to dig that bit deeper in your pockets. On balance, we'd say it was worth it.

The IBM Thinkpad X30 is an excellent sub-A4 notebook offering speed, great battery life and good ergonomics in a light, robust and compact package. It doesn't come cheap, of course, and you have to fork out more for the floppy and optical drives and docking base, but there's no doubt that the Thinkpad X30 is a cut above.