Saturday morning and I find myself with a moderate sized hang over (family wedding, since you ask) standing in Gatwick Airport trying to work out how I get to the railway station.

I'm staring at a sign that reads "for arrivals follow the illuminated signs".

It's the word illuminated that's got my attention. I'd never noticed before, but as soon as you look you realise that all the yellow signs everywhere in the airport are backlit by what must be several thousand bulbs. Every last one of them is illuminated, even at ten in the morning on a bright sunny day.

One question: why?

What was so wrong with all the old signs? You know the ones: white background, black fonts, worked perfectly adequately for centuries.

I don't doubt BAA could trot out some kind of spurious business case for these signs. It would probably quote a research project somewhere that has shown that backlit yellow signs are the easiest to spot when you are hurrying to the gate - that the illumination makes it easier for the myopic amongst us to read the signs at a distance. They'd probably add that all the bulbs used are energy efficient.

But I'm not sure I buy it, particularly when you consider that airports, like shopping malls and most other public spaces, are typically hyper-illuminated forums, capable of giving you a headache regardless of what you were up to the night before.

I don't believe that prior to some bright spark deciding to illuminate many of the signs that we are bombarded by everyday we were all constantly wondering around getting lost and confused. Even if the most efficient bulbs available are used, the benefits of the illuminated signs are surely so marginal as to be outweighed by the environmental and financial cost of the energy they are using.

It is always difficult to advocate ditching a technology in favour of a simpler alternative. It is too easy for such a move to be accused of being regressive, even luddite, in its thinking.

Ask public spaces to ensure signs are only illuminated when it is dark and anti-environmentalists will inevitably try and lump you in with those killjoys who call for an end to Christmas lights or turn their nose up at any technological product that has the faintest whiff of frivolity.

And yet, as resource scarcity issues mount and pressure to cut energy use becomes more acute, perhaps it is time for more firms to ask if the technologies they use have been over-engineered. If the original, low tech version a product replaces could not continue to do the job just as effectively?

Technological progress is, of course, essential to the transition to a low carbon economy and new low carbon product need to be developed at a breakneck pace over the next two decades. But for every low carbon leap forward achieved by engineers and scientists, a new over-engineered technology emerges that threatens to negate some of the environmental gains achieved while delivering only a fractional, or in many cases non-existent, improvement on the product it aims to replace.

My personal recent favourite were the reports of a new installation in the changing rooms of a New Look store in Birmingham that uses a video camera and plasma screen TV to allow shoppers to tell what the clothes look like from behind. Because, apparently mirrors just aren't good enough anymore.

That, and the electronic post it notes that beep at you if you forget to do the things on your to do list.

It is not regressive to suggest that some technologies have reached a level of perfection, or at least satisfactory competence, whereby further "improvement" can not be justified in a resource strapped world. The sooner firms realise this, the easier they will find it to focus their attention on the genuinely sustainable technologies and business models that promise to reduce both their running costs and their carbon emissions.