Insurers should adopt "prudent avoidance" when dealing with the risks associated with electromagnetic induction (EMI), according to an industry expert.

John Bryant, managing director of research and development company Xetal Consultants, said that the health risks of such radiation, emitted from many electronic devices as well as mobile phone aerials, remained unknown.

But he said that there was some evidence to suggest that EMI could damage the central nervous system as well as cause other health problems.

Bryant told an International Underwriting Association briefing that the risks associated with the terrestrial trunked radio system, (known as TETRA), used in the UK for police communication, were of particular concern.

Lloyd's and Swiss Re were among the insurers to exclude electromagnetic risks, but Bryant said another option for underwriters was to ensure that buildings are 'screened' against external EMI using glass and wall screens.