I wonder if our lords and masters (our servants really, although that's difficult to believe) ever consider the environmental consequences of their decisions? Take the national identity card. Will the storage drives need to rotate perpetually in case anyone decides to check us out? Or could the forces of law and order be happy to wait while a drive is fired up and rummaged? If the drives are running continuously, has anyone worked out how much energy would be needed to run them, the computers that access them and the systems needed to cool them?

My guess is that the people who conceive these surveillance projects do not bother themselves with such matters. Yet, even if we're not yet running out of energy, it gets more expensive by the day and, of course, most of it contributes to the carbonisation of the planet. Surely any politician worth their salt would be careful before burdening the atmosphere with more CO2?

Which brings me to the British Library and its Microsoft-sponsored digitisation project. It's been worrying the hell out of me. I've been thinking of all those computers and disk drives sustaining substantial quantities of material that's going to be looked at only rarely. It makes no sense. But then offline tape storage doesn't make sense either.

Fortunately, a company called Nexsan has provided the Library with an answer. It's invented a MAID, a Massive Array of Idle Disks. They sit around quietly stationary until they're woken up by a request for information. This approach, according to Nexsan, cuts energy use by 96 percent. It gives an example of a conventional fibre channel storage device which consumes 187KW of energy per petabyte, whether it's being accessed or not. Its own Nexsan Assureon system in Level 3 AutoMAID idle mode consumes just 6KW.

It makes you think, doesn't it? Especially if your organisation has massive amounts of 'Just in case' storage.