MOBILE PHONES: WHAT THE EXPERTS SAY

THE ONLY clear "threat" posed by mobile phone masts is to the view, according to the National Radiological Protection Board (NRPB). As Britain's watchdog on the health effects of all sorts of radiation, from sunlight to X-rays to nuclear tests, the NRPB has a legal duty to warn the public if it perceives any danger from the emissions from mobile phones or the masts they need as a "base station".

So far though "there is no evidence of adverse health effects," said the NRPB's Dr Mike Clark, "although the number of calls we get about this is astronomical compared to anything else."

Mobile phone masts appear to pose less risk than television transmitters, which have been around for decades. "A mobile phone mast often has an output of about 60 watts. A TV transmitter can be 1 megawatt - that's a million watts," said Dr Clark. "It's the same with radar, which has been around for ages. There are no obvious health effects from long-term, low-dose exposure. Often people who are protesting about the proposed siting of a mast near a school. But when we get there and measure the emissions, we find that the biggest emitter in that microwave frequency is TV."

The NRPB was among the first organisations in Britain to warn about the risk of sunburn leading to skin cancer, and in the 1980s urged lower limits on exposure to radioactive materials after studying data from Hiroshima, where thousands died after the world's first atom bomb attack in 1945.

Microwaves from any sort of transmitter can be dangerous, because they will "cook" you just like a microwave oven cooking a piece of meat. Last year Edward Baker, 31, a night watchman at a telephone relay company in Manitoba was killed when he tried to keep warm by sitting in front of a telecomms dish which used microwaves to relay thousands of telephone conversations.