Here is a picture. A man is sitting in a room, surrounded by other people, all of them stabbing at small pieces of plastic, while televisions blare and smoke hangs in the air. (The press room at any political party conference, deadline approaching .) Suddenly the man changes colour.

A line of crimson washes up over his shirt collar, lunges across his face and disappears into his hairline. The man leaps up, back arched. He starts to dance around the room. Foul words pour from his mouth, profane plosivesthought up in some Anglian bog during one of the less pleasant bits of the Dark Ages and rarely heard since. The man's colleagues stab on, for they have become used to this behaviour.

The man, O Reader, is myself, and I have been using a Dell Latitude notebook computer, lent to me by the Network Page. This, I have been assured, is an object of desire, the hottest little laptop in the West, the sort of kit that will get its owner admiring stares. If I saunter round the political conferences carrying this, I will be an object of attention. Well, they were right about that, at least.

Apparently the point of the Dell is that it has a battery that lasts for eight hours, so you can do things such as use it on the train. On the way to Blackpool, I couldn't. The in-built mouse jerked and leapt across the screen to the rhythm of the British Rail rumba; the keyboard design, with a fat slice of plastic between you and the keys, makes typing harder than on simpler, cheaper machines; and my eyes ached.

None of that, however, matters so much. What caused the real spasms of anger was that my machine suddenly closed itself down without warning. When I restarted it, the copy had gone. If one has just spent three hours honing and polishing a thousand words,this can seem a less-than-endearing trait. If there are only minutes left to deadline, then a fellow, however naturally amiable, might feel a trifle narky. If it happens three or four times, then only the thought of how much the thing costs prevents a chap from flinging it through the nearest plate-glass window.

A final irritating problem was the unreliability of the communications system, which seemed to connect to the office less often than the allegedly plain and unglamorous Tandy laptops that I had used in the past. Again, if one is short of time, and requires a measure of predictability, this failed my road test.

No doubt this machine can do lots of brilliant things I do not know about. No doubt it can play games involving mentally deficient barbarians, nuclear-tipped dragons and hooligan hedgehogs, while reconstructing the tax exposure of Mitsubishi Electric on a spreadsheet across which pink and avocado-coloured toasters are flying to the strains of Handel's Samson. But all I wanted to do was write sentences and send them through a telephone line, and I wasn't impressed.

Next time, I'll indent for a Biro, a notepad and a pocketful of 50p pieces.

Andrew Marr is Chief Political Commentator of the `Independent'.