Major 30-year study launched by UK government research centre into health effects of mobile phones.
Professor Challis, the former head of the government-funded Mobile Telecommunications and Health Research programme (MTHR), said: ‘I think it is plausible because their immune system is still developing and we do know that children are more sensitive to other things, for example ultra-violet light.
'If a child is exposed to excessive sunlight, they are more likely to get skin cancer than an adult exposed to the same amount.
‘They are more sensitive to pollutants. There is a thinking that they might be at increased risk.’
He acknowledged that some parents may get peace of mind from giving their young child a mobile phone.
But he added: ‘I don’t see why with young children one shouldn’t be a little bit more firm as a parent and say there are reasons why they think it is not a good idea, unless there are specific safety reasons why it needs to be done.’