No hard evidence exists to show mobile phones damage health but users - especially children - should take care, UK scientists said in a survey Tuesday.

Britain’s National Radiological Protection Board (NRPB), an independent advisory group, said there have been reports of adverse health effects but some have not yet been independently confirmed and are of variable quality.

“We are still recommending a precautionary approach because there is still no hard evidence that the health of the public in general has been adversely affected by the use of mobile phone technologies,” NRPB chairman Sir William Stewart told a news conference.

But Stewart added that he did not think he could put his hand on his heart and say mobile phones are totally safe because the technology is relatively new and is evolving so rapidly it is outstripping the analysis of any potential impact on health.

Some research suggests radio frequency fields could interfere with biological systems but it has not been possible to carry out long-term studies.

The Mobile Operators Association in Britain, which represents operators on health and planning, welcomed the report.

“The key point of the NRPB advice is that there is no hard information linking the use of mobile telephony with adverse health effects,” said its executive director Mike Dolan in a statement.

CHILDREN MAY BE MORE VULNERABLE

Children might be more vulnerable because their nervous system is still developing, they have a greater absorption of energy in the tissues of the head and they would have a longer lifetime exposure than adults, according to the report.

Stewart recommended children use mobiles phones for as short a time as possible. They should text instead and use a phone with a low SARS value. Specific Absorption Rate (SAR) is the measure of the rate of energy absorption in body tissue.

“We have got to be cautious. We can’t say there will be no effects,” he added.

Mobile phones have become a $100 billion a year industry. About 650 million are expected to be sold to consumers this year and over 1.5 billion people around the world use one.

Third generation, 3G phones, which emit higher rates of radiation than earlier models are now marketed in Britain and elsewhere.

The report also called for the monitoring of base stations, including new 3G stations and Terrestrial Trunked Radio (TETRA), used by police.

Stewart said studies suggesting mobile phones can cause non-malignant brain tumors, cognitive impairment or DNA damage should be not be dismissed but more research is needed.

“The general public, the man in the street, must be able to get information easily and he must be able to get it readily,” he added.