The network needs more than 200 Tetra masts across the south west to provide effective cover - half already have planning permission.

But villagers in Ashton in West Cornwall, one of the planned locations for a mast, are worried about the health risks and the threat to the environment.

Airwave, the company installing the system, says that the latest scientific advice concludes there is no evidence that Tetra technology poses a risk to health.

My personal view is that this system is still in its experimental phase and I don't particularly want to become a guinea pig

John Keeling, parish councillor

Airwave says the service is vital as it will improve the efficiency of the police.

"It's the equivalent of putting more bobbies on the beat," said Mark Ede from Airwave.

"In disaster situations it will save lives, and I think that it is essential that the emergency services have first class communication systems."

Villagers at Manaccan on the Lizard fought to stop a mast going up there and in Ashton a number of landowners have already refused have masts on their land.

"We have got to prove that this system is safe beyond a reasonable doubt, " said John Keeling, an Ashton parish councillor.

"My personal view is that this system is still in its experimental phase and I don't particularly want to become a guinea pig.

"What we need is independent research to prove that this system is safe."

The communications network is due to go into operation next year but the protest could now put a question mark over that date.