Government advisers dismissed fears yesterday about the health risks of mobile phone radio masts.

They agreed there was no substance to concerns about base stations, which relay signals to and from phones.

The scientists said they could not rule out the possibility of adverse effects from handsets - although they, too, appeared to be safe.

But they were much more confident about the safety of radio masts, which have caused some of the greatest controversy over exposure to mobile phone radiation.

In its report the advisory group on non-ionising radiation (Agnir) said: "Exposure levels from living near to mobile phone base stations are extremely low, and the overall evidence indicates that they are unlikely to pose a risk to health."

The siting of mobile phone masts, especially near schools, has been strongly opposed by some communities. In December 2000 a protest group, Mast Action UK, was launched to provide a national voice for people worried about the health hazards of base stations.

Some studies have suggested that microwave radiation of the kind transmitted by mobiles and masts may be linked to brain tumours, sleeping disorders, memory loss and miscarriages.

Today's report said the claims were not backed by consistent scientific evidence.

One member of the group, Professor Lawrie Challis, from the University of Nottingham, said radiation exposure from base stations was at least 1,000 times less than it was from mobile phones.

Speaking on a mobile phone for just a few seconds was equivalent to standing in the direct beam of a mast for 24 hours.

More than 47 million British adults have a mobile phone - about 70% of the population. Mobile phones are more popular in the UK than in the US, where only 40% of people have one.