Northumbria Police is set to become the seventh force in the UK to use Airwave, the controversial communications network for the emergency services based on Tetra.

Officers in the region are due to begin using the service later this month.

Under a £2.9bn deal mobile phone operator mmO2 is to install the Tetra technology across all 53 police forces in mainland UK by the end of 2005. Over the next twelve months mmO2 hopes to roll out the service to a further 25 forces, including the Metropolitan Police.

A spokeswoman for mmO2 said the police were already seeing benefits to the new service.

"There are many anecdotes from those forces that it is proving to be beneficial in operational situations, and the police have been able to catch criminals as a result of using Airwave," she said.

Officers in both Lancashire and West Mercia have apprehended criminals carrying analogue radio scanners. The criminals had expected to monitor police whereabouts, but this was prevented by Airwave's encrypted radio system.

But there were still questions over the effectiveness and safety of the handsets. As reported by vnunet.com, police officers are claiming the new digital handsets are making them ill.

A spokesman for the Police Information Technology Organisation said the Home Office was still in the process of investigating the claims.

"We recognise that some officers have expressed concern about the technology but we are doing everything we can to reassure them," he said.

mmO2 admitted there would be "some small problems as we go forward," because of the scale of the nationwide roll-out.

The spokeswoman said, however: "We work very closely with the police forces and the Home Office to minimise those problems. What we are looking at is a highly detailed piece of technology and we are trying to smoothly integrate new technology with an old technology."