Letter: In Brief

Sir: So mobile phones "can make you smarter" and "significantly improve the speed [of] mental tasks" while they are switched on. Before the manufacturers blow a smug raspberry at cautious critics, might I remind people that amphetamines have the same temporary effect, but no one would dispute the damage done by long-term use. The onus should be on the makers to prove safety beyond all reasonable doubt.

J PHILLIPS

Newcastle upon Tyne