The question of possible adverse health effects of mobile phone base stations has received attention once more, this time in Simon Busuttil's regular Wednesday column (September 17). Based on the available scientific evidence Dr Busuttil rightly states that there is no evidence that mobile phone base station antennas are a cause of adverse health effects.

For the reasons outlined in Dr Busuttil's reply, mobile telephony base stations clearly do not pose a health hazard. On the other hand, it is still accepted that further research is needed to better understand the possible effects, especially long-term, of hand-held mobile phones on health.

One can therefore reasonably say that the jury is still out on the question of the hand-held mobile telephone. This is on the basis that, if microwaves do pose a health threat, this would sooner be from hand-held telephones and not from the base antenna which are too far away to cause any harm.

The situation is different with hand-held telephones; these emit microwaves while held pressed tightly against the ear - literally within one inch of our hind-brains. Mobile phones can have a power output as high as one watt; roughly calculated, this exceeds the maximum allowable leakage from a microwave oven by a factor of three.

This (unlike a base antenna) can raise the temperature of the user's brain by as much as 1°C. For this reason the British Medical Association and other expert bodies, recommend a precautionary approach to the use of hand-held mobile phones by children. The official recommendation is to limit the use of mobile phones by children, namely, to avoid as far as possible giving children mobile phones and - if they already possess them - to allow them to use them as little as possible. This makes sense even though there is still no firm evidence that hand-held mobile phones are harmful.

To date, the only clearly proven danger of mobile telephony is a significantly increased likelihood of a traffic accident resulting in injury (to drivers or pedestrians) when drivers use a mobile phone while at the wheel; curiously, this applies to hands-free phones too. Police, please note.