It's not often that the UK benefits from a run of decent, sunny weather. But we're doing fairly well in this respect at the moment, and global warming may increase our chances of fine weather in future years (assuming it doesn't go all monsoony instead). In such sunny times, it would be nice - especially if you work from home - to do a bit of work outdoors.

In fact, why not? Yes, I'll just charge up the laptop, take it into the garden, switch it on and... squint. Completely useless; the screen is unreadable because its puny back-light can't compete with the glare of the massive hydrogen furnace beating down from above. I know that laptops work well in the office and in the house, but when you're truly out and about (on the train, in the park, at the airport), the lighting conditions can soon render the brightest screen useless.

The problem is that laptop manufacturers are competing with ambient lighting wherever they go. In many situations, particularly in offices lit by fluorescent strips, they'll win. But in many others they'll lose. The problem is even worse when using a colour PDA, since these palmtops also have back-lights. Yes, they're bright, but they're not much use in direct sunlight, which is where many of them will be used.

There are alternative types of screen available. Transflective (rather than transmissive) screens, use ambient light to provide contrast with what's displayed on the screen, so they get easier to read as the light gets brighter. They have back-lights too, for use in darker places, but unfortunately these screens are only really appropriate for monochrome displays - so no colour.

Properly reflective displays should be here within a couple of years. These should appear much like paper, with easy-to-read lettering on a flexible sheet of plastic material. But they'll be expensive to start with and there may be unforeseen teething problems.

And anyway, I can't wait a couple of years. It might be the rainy season in London by then. What am I going to do? I've got an old Psion 3mx here with an external keyboard attached. Its monochrome screen is transreflective, so it gets easier to read as the ambient brightness increases. Fantastic. Although if the weather gets much hotter, the LCD crystals start to polarise the light too much, and everything goes dark again.

Ah well. It's too hot to work, anyway.