Thousands of police officers using a controversial new digital police radio system will be monitored to see if it affects their health.

Members of North Yorkshire's force will be among 100,000 officers involved in the Home Office study which aims to reassure people of the safety of the Airwave system.

North Yorkshire was one of the first eight forces to begin using the technology, which cannot be scanned by criminals and reduces radio "black spots".

The digital system cost police chiefs in the county £2.1 million to install and has running costs of more than £1 million every year.

The building of new masts to link the network met with fierce resistance in the North York Moors National Park, as residents claimed they would emit damaging radiation.

Deputy Chief Constable Peter Walker said he welcomed the £5 million study, which will be conducted by experts at Imperial College, London.

He said: "I welcome this announcement. I am quite certain that the Airwave system is safe and offers great advantages to the police service.

"However, for those who have worries about the system, these studies will provide the reassurance they have been looking for."

Home Office ministers claim the communication system will enhance the effectiveness of officers out on the beat, as well as helping to keep them safe.

They said independent experts and Government-funded research have already shown that Airwave is safe to use but the new study demonstrates the Government's commitment to health and safety.

Home Office Minister Bob Ainsworth said the health of officers was his top priority. He said the health-monitoring programme would provide further reassurance to users about long-term safety.

He said: "Officers appreciate the operational benefits of Airwave and can be reassured that we will address proactively any concerns they may have."

In February, the Government announced that North Yorkshire Police would receive an extra £4.45 million in special grants, and that part of the money would be used to introduce the new Airwave system.

Updated: 10:19 Monday, May 26, 2003