There is a school of thought that says the days of the traditional ISP are numbered. Why? Because of mobile broadband. With every UK operator now offering a modem that uses USB, is self-installing under Windows XP and Vista, and that offers connections for download at up to 3.6Mbps, you can see why.

These modems are really designed for use out and about with laptops but there is nothing to stop you plugging one into your desktop PC when you want the connection there. If there is a price war, and unlimited access comes down to a point where it competes with traditional ISPs, then the choice between fixed and mobile broadband is a no-brainer. I'll take the mobile, please.

Vodafone isn't content with the 3.6Mbps scenario, though, and has started to roll out 7.2Mbps download speeds. Starting in December last year in a few Central London postcodes and some airports, the plan is to gradually increase the coverage. Along with this launch came two modems capable of the higher speed.

Both are USB devices, and both are available for the same pricing, which could be free depending on your contract choice. The boringly named USB Modem 7.2 is a bar-of-soap style device, white in colour, with a red band that pulses when data is being transmitted. It connects via a USB cable and comes with short (19cm), and long (80cm) cables.

Meanwhile the USB Modem Stick is, as its name suggests, designed to plug directly into a USB port. It is smaller than the USB Modem 7.2 and looks like a slightly oversized flash drive. It comes with a cable which could prove very handy if the stick obscures a second USB port that you want to use, as it did on our test laptop.

The desktop software which self installs when you connect either modem to your laptop or PC includes an SMS module with contact manager. It shows data usage in both volume and time for the current and previous months, which is handy if you are on a limited use tariff and need to keep an eye on things.

During testing both modems worked perfectly. We were not in a 7.2Mbps zone when we tested them, but they both found a 3.6Mbps connection and worked with that. You can tell what speed you are connected at by the colour of a light on each of the modems and by checking the desktop software.

Finding a 7.2Mbps connection is likely to be a challenge for many at this stage, as only some airports and London postcodes are up and running. However, Vodafone does have plans for a wider rollout, and in the meantime the 3.6Mbps connections should be solid and stable if our experience is any kind of indicator.

The plug and play system really does work, and both modems are stylish to look at and small to pocket. As we said at the start, if the tariffs start to fall on unlimited access, fixed line ISPs will need to watch their backs.