Sony would have us believe its new tiddler-sized VAIO P-series notebooks are ultra portables, not netbooks. In our early trial spent with the range, we would agree that they're certainly more portable than even the smallest netbook. But they're also much more expensive.

There are three models to choose from, starting with the VGN-P11Z at £849, then the more business-oriented VGN-P19WN/Q at £969, and a faster VGN-P19VN/Q for £1368.

The first two versions share a specification that includes 1.33GHz Intel Atom processor and 60GB hard drive. To differentiate the business model it comes only in black, has Vista Business installed, and includes a port expander which adds ethernet and VGA video out.

The top model uses a 1.66GHz Atom with 128GB SSD for storage. All P-series notebooks include 2GB of RAM, an 8in ultra-wide 1600x768 glossy screen, and a port complement of two USB and a headphone socket.

There's a webcam and mic, and two card slots - one for an SD Card, the other for Sony's Memory Stick. They all include a 3G modem, only requiring a valid SIM card to get online wirelessly.

For mousing around there's an IBM-style pointy stick in the middle of the keyboard. And the small hi-res display means the tiniest screen fonts and Windows buttons you can imagine.

At 245x120x20mm it's one of the smallest portable PCs you'll find, smaller than just about any computer running a traditional operating system. Think Psion organiser with Windows.

But then again, the P11Z is also conspicuously less powerful. Any compact computer must find the balance between weight, size, heat and battery life. Our hands-on showed that Sony has nailed the weight and heat issues. It never got hot, and at 638g the VAIO P is an extremely lightweight proposition. Performance did suffer though. Badly.

The problem's exacerbated by Sony's bewildering choice of operating system. Windows Vista is installed across the board, with no option to sidegrade to Windows XP. Sony had even downgraded the Aero interface to Basic, just to get video to play.

Ergonomics aren't great either. The keyboard has tiny keys with limited travel, making fast typing a no-no. And the trackpoint will not endear itself to those who welcome the more versatile trackpad.