Toshiba's Portégé R600 sets a new standard for lightweight ultraportable laptops, making it an attractive option for workers who need to carry a PC with them.

However, this portability comes with the drawbacks of a short battery life, high purchase cost, and a design that feels like it may break unless handled carefully.

Available since late 2008, the Portégé R600 has a 12.1in display, built-in 3G broadband modem and a footprint approximately the size of an A4 sheet of paper. It is a slim-line design at just 19.5mm thick at the front and 25.5mm at the rear when closed. But it is the weight of this model that is so extraordinary. At just 773g, it feels like picking up an empty shell rather than a fully functioning laptop PC.

This would seem to make the Portégé R600 a dream machine for users such as travelling executives, but it is hard to justify the £1,600 price tag of our review unit. Even the entry-level R600 will set buyers back at least £1,000, which seems steep when you consider that netbooks with 10in screens can be bought for £300.

Toshiba would no doubt argue that the R600 is a professional business tool and that netbooks are consumer products. But, apart from a bigger screen and a larger memory for running more demanding applications, it is difficult to see where all of the extra cost is incurred.

The plastic-looking silver styling also does Toshiba no favours, and in our opinion makes the R600 look cheap and nasty rather than a premium product.

We also had reservations that the lightness of the R600 might make it prone to being easily damaged. The screen, for example, flexes quite substantially, but Toshiba said that the display is designed to do this to prevent damage.

The system also includes a motion sensor to protect the hard disk, and a spill-resistant keyboard as part of Toshiba's EasyGuard features.

Our review unit was a Portégé R600-108, which is based on an ultra-low voltage Core 2 Duo U9400 processor running at 1.4GHz. This model comes with a useful 3GB of memory, plus a 128GB Flash solid state drive.

Other R600 models are available with hard drives ranging from 160GB to 320GB, and with an internal DVD Super Multi drive absent from this model. The latter option pushes the weight up to 1.114kg, which is still impressive for a full-spec laptop.

The Portégé R600 ships with Windows Vista Business edition by default, and we found its performance satisfactory under this, and more than adequate for running applications such as Microsoft Office. With 3GB of memory, it should be capable of handling even fairly weighty Excel spreadsheets, for example.

Under Vista's built-in Windows Experience Index the Portégé is rated at 3.1, but this score is pegged back by the performance of the graphics subsystem. The processor, disk and memory subsystems all showed above average scores.