The recent scare about the risk of brain cancer from the use of mobile phones bears a certain similarity to those long-running scares we have suffered on the risk from using the oral contraceptive pill and the risk from pylons carrying high-voltage power lines ("Health experts say mobile phones may cause cancer", The Herald, June 1).

As in all such controversies, it may take many years before enough data is gathered to give meaningful and reliable statistics to quantify the risks involved.

In the meantime, can we give meaningful advice to people? Especially, can we advise parents who have been scared by the (quite reasonable) advice that children’s brains are more likely to be vulnerable to harmful effects of radio-frequency radiation from mobile phones? The answer is yes.

If we assume that a phone held to the ear is 2cm from the listener’s nearest brain tissue, then we know from basic physics that if the listener switches to speakerphone and holds the phone at a comfortable distance of 63cm from his head, the radiation dose received by that tissue will be reduced to a mere one-thousandth. Since the evidence so far available suggests we are facing a fairly low risk of damage from mobile phone use, this simple manoeuvre to reduce the risk by one thousand-fold will, I hope, reassure even the most cautious users that they can be safe from brain cancer.

They may, of course, not be so safe from the effects of allowing those around them to hear their conversations.

Dr Willie Wilson,

57 Gallowhill Road,

Lenzie.