The debate over mobile phone safety has split the science world into two camps: those who believe they pose a potential health risk and those who don't.

In their relatively short history, mobiles have been blamed for causing all manner of ills, including cancer, headaches, memory loss, high blood pressure and strokes.

The abundance of claim and counterclaim has doubtless left you scratching your head - although this should not be regarded as yet another side effect.

According to George Carlo, the mobile phone industry has pulled the rug over findings that query the safety of the world's 200 million handsets.

There are more than 15 million mobile phones in Britain

Dr Carlo says the rate of death from brain cancer among people who handheld mobiles to their head was higher than those who used phones away from their head.

What gives Dr Carlo's claims weight is that his research was commissioned and paid for by the industry, to the tune of £15m.

He also says the risk of developing a type of benign tumour is twice as high in people who used a mobile for six years or more, and that the risk of developing a rare tumour on the outside of the brain is more than doubled in mobile users.

His latest step has been to invite them to come clean and asking then to include health warning leaflets with each phone sold.

But the industry insists media hysteria has overtaken rational debate, and that there is no conclusive evidence either way.

Police caution

The message that something may be wrong has certainly filtered down to street level. A Mori poll earlier this year revealed 43% of regular mobile phone users were worried about the scare. The Metropolitan Police is one of many employers to advise staff to limit their time spent on mobile calls.

Emissions fall within safety guidelines, manufacturers say

What is certain is that many mobile phones emit microwaves which would be considered harmless, but for the fact that phones are held so close to the head.

A study commissioned by BBC's Panorama in May found large differences between the amount of microwave radiation absorbed by the brain from different makes of phone.

But manufacturers say the amounts fall within safety guidelines and a report by the New Scientist earlier this year dismissed the notion that these microwaves could "cook" the brain.

"A mild bout of exercise will heat your head more than the puny microwaves that the devices emit," said the article.

Last month, an all-party committee of MPs agreed there was no firm evidence that mobile phones pose a threat to health.

Yet the public looks set to maintain a cynical view and research continues around the world.

Several major studies are currently underway, including one at Bristol University.

It is researching claims that mobile phones may alter the way blood flows in the head, after a German scientist, Dr Stefan Braune, found their use increased blood pressure.

Many customers are resorting to hands-free appliances

Dr Alan Preece, who will lead the investigation, is no stranger to this field. A previous study led by him found that microwave emissions had no measurable effect on short-term memory.

In fact the research revealed that rather than slowing people down, mobile phone microwaves actually slightly increased people's reaction speed.

Meanwhile, phone manufacturers and other companies are doing brisk business in add-ons which are seen as minimising radiation emissions.

Customers are increasingly resorting to using hands-free attachments and radiation shields. Microshield, has sold more than 35,000 of its radiation guards, at £39.99 each.

Clearly, there is money to be made from the on-going confusion.