No convincing evidence has been revealed that mobile phones damage human health in spite of an "explosion" in research into the issue over the past decade, according to a review of scientific studies billed as the most comprehensive yet.
Driving while using a mobile phone remains the one established health risk of mobile phones, a leading scientist said as a report on exposure to radiofrequency (RF) electromagnetic fields emitted by devices such as mobile phones was published.
The review found that a large number of studies have been published on cancer risks in relation to mobile phone use but overall the results have not demonstrated that the use of mobile phones causes brain tumours or any other type of cancer.
But the report, from the Health Protection Agency's (HPA) independent advisory group on non-ionising radiation (AGNIR), warned that it was "important" to continue to monitor all the evidence as there was little information on the risks beyond 15 years from first exposure.
This monitoring should include monitoring national brain tumour trends which have so far given "no indication" of any risk, the report recommended.
The HPA said it would continue to advise a "precautionary" approach and keep the science under close review.
The agency recommends that "excessive" use of mobile phones by children should be discouraged while adults should make their own choices as to whether they wish to reduce their own exposure.
Professor Anthony Swerdlow, chairman of the AGNIR and an epidemiologist at the Institute of Cancer Research, said the last similar large-scale review by the group had been carried out in 2003 but since then much more information had been made available.
He said there were still limitations to the published research that meant a "definitive judgment" could not be given but the evidence overall has not demonstrated any adverse effects on human health from exposure to radiofrequency fields below internationally accepted guideline levels.
"There has now been a very large amount of research conducted, which wasn't true 10 years ago, and we have much firmer information than we had on several areas, for instance symptoms, cognitive effects, brain tumours, than we had then," he said.
"There is no convincing evidence that radiofrequency exposure causes health effects in adults or in children but beyond 15 years for mobile phones, we have to say we have little or no information.
"I think it is important therefore, to some extent, to keep an eye out on this, which we will do into the future."
He said there was a need to keep a "watch" on national cancer trends, particularly for brain tumours. So far, brain tumour rates were not rising in the age groups exposed for the last 10 to 15 years, he said.
"Remember this is an exposure that 20 years ago nobody had and now practically everybody has so you might expect that if there were appreciable effects that you would see them in the tumour rates," he said.
"But if this is something that takes 15, 20 years or more to show up - we have no reason to think there is an effect - if it takes a long time to show up, we need to keep watching the rates just in case."
Dr John Cooper, director of the HPA centre for radiation, chemical and environmental hazards, said: "The HPA's position on mobile phone technologies is in line with the AGNIR's findings.
"There is still no convincing scientific evidence that RF field exposures from mobile phones and other radio technologies affect human health at exposure levels below internationally agreed guidelines.
"However, as this is a relatively new technology, the HPA will continue to advise a precautionary approach and keep the science under close review.
"The HPA recommends that excessive use of mobile phones by children should be discouraged and mobile phone-specific energy absorption rates values should be clearly marked in the phone sales literature."
A Department of Health spokeswoman said: "There is no current evidence to suggest a health risk for adults or children from mobile phones.
"The independent advisory group keeps all evidence under review and continues to recommend that excessive use should be discouraged."