Smart scanners

It's a question that has arisen again and again in recent years: how do we balance an individual's right to privacy against the obvious and increasing need for global security?

On one front at least, a compromise has been struck. The US Transportation Security Administration has begun replacing its controversial, invasive "naked" security scanners at major airports with machines that display a generic cartoon-like image of a person's body yet can still detect weapons or other security threats.

The new machines, known as millimetre-wave scanners, operate more quickly and do not require a second security officer in a separate room. They also use low-level radio waves rather than ionising radiation, which could pose a health risk with repeated exposure.

These are all sound reasons for the change, but civil libertarians and people who are simply concerned about having the intimate outline of their body revealed to strangers will see this as a victory - even though the existing machines are being relocated to airports with smaller passenger volumes rather than being consigned to the scrapheap.

This is a creative solution to a problem that satisfies all parties. But it raises the question: why didn't somebody think of this in the first place?