UK police and fire fighters will be exposed to dangerous emissions that can damage brain tissue and cause leukaemia and lymphoma from their own multi-billion pound radio equipment, Network News can reveal.

Leading biophysicist Dr Gerald Hyland, of the University of Warwick, has warned that a lack of thorough research and a refusal by regulatory bodies to listen to complex scientific arguments means that Tetra users are potentially being put at risk.

"If the same level of uncertainty surrounded a new drug, it would never be licensed," he said.

"Tetra operates at higher powers than GSM and over a wider range of microwave carrier frequencies," Hyland added. "More disturbing is that its basic frame repetition rate is 17.6Hz, a frequency close to that at which a flashing light can provoke seizures in people with photo-sensitive epilepsy."

He claimed that Tetra emissions were even more dangerous because the lower frequency band assigned to the emergency services, 380MHz to 400MHz, can penetrate deep into human tissue. "The penetration of Tetra radiation is much greater than with GSM, facilitating deeper access into the brain directly through the skull," he said.

The comments will ring alarm bells among emergency services chiefs already concerned about fears that Tetra poses a serious threat because the technology produces sparks that can ignite flammable gases.

A spokesperson for the London Fire Brigade said: "In the next couple of months we will invite tenders for a new radio system. The health and safety of all applicants' technologies will be thoroughly investigated. If our scientific advisors find any suggestion that the equipment is not intrinsically safe, we will not use it."