Concern about the safety of mobile phones has prompted a leading Lloyd's underwriter to refuse to insure phone manufacturers against the risk of damage to users' health.

The move comes amid mounting concern about the industry's influence on research into the long-term effects of using a mobile.

The London market provides insurance for everything from aircraft to footballers' legs. But fears that mobile phones will be linked to illnesses such as cancer and Alzheimer's disease have prompted John Fenn, of underwriting group Stirling, to refuse to cover manufacturers against the risk of being sued if mobiles turn out to cause long-term damage.

New research published last week by Bristol University scientist Dr Alan Preece showed a 'highly significant' effect from mobile phone signals on brain function. Some previous studies linked mobiles to increased tumours in rodents, but they have been contradicted by other research.

The Government has ordered the National Radiological Protection Board (NRPB) - responsible for monitoring radiation safety standards in everything from Sellafield to sunlight - to set up an independent group to identify possible areas for research.

Liberal Democrat MP Phil Willis, who is pressing for a fuller parliamentary debate on the issue, condemned the initiative as a sop to the public and a sop to the industry'.

He said: 'I have asked three network operators if they will give insurance against future health risk, and they have all said they cannot.'

The Federation of the Electronics Industry, which represents mobile phone manufacturers and networks, said there was no proven reason for insurers to refuse cover. Spokesman Tom Wills Sandford said: 'I am surprised. I would be confident that there would be people who would cover that risk, because there is no scientific proof of health risk.'

But Fenn said: 'There are people in the insurance market who close their eyes to the issue because they say there is no scientific proof of a problem. If you go back to asbestos, it "wasn't a problem" at one time either.' Asbestos claims helped bring the Lloyd's market to its knees in the  early 1990s.

Experts at the NRPB say they cannot give mobile phones a clean bill of health until comprehensive research has been carried out into the non-thermal effects of microwave radiation emitted by handsets. Until now, the vast majority of research has been funded by the industry: there are 78 industry-sponsored studies under way worldwide, while governments fund only 14.

The Department of Health says a new working group will be established, including industry and consumer group representatives, but its membership has yet to be agreed.

Concerns are increasing about the industry's involvement in research. Some of the NRPB's conclusions have been based on research by Dr Camelia Gabriel, a technical adviser to network operator Orange and head of private consultancy Microwave.

Her colleague, Professor Ted Grant - who, with Gabriel, helped draw up Orange's health and safety brochure - was until recently a board member of the NRPB. There is no suggestion that Gabriel or Grant's findings have been biased as a result of their industry links.

But Willis, who has won the support of more than 108 other MPs, said he was 'extremely worried'.  'The Government needs to fund proper, independent empirical research into the biological, non-heating effects of mobile phones,' he said. 'I am concerned about the potential influence of multinational companies on these studies.'

The NRPB's budget for mobile phone research is currently just £300,000 per year. The Department of Health has not yet indicated how much funding will be
made available for future research.