BARELY half of Wiltshire's countryside remains undisturbed by development, a study has concluded.

The Campaign to Protect Rural England has published maps charting the spread of "noise and visual intrusion" from urban areas into the countryside since 1960.

And it reports that Wiltshire has seen 16 per cent of its countryside affected by urban development since 1990, meaning that 46 per cent of the county now suffers from such intrusion.

Most worrying is the claim that Wiltshire's countryside has deteriorated almost twice as fast as the national average since 1990, which is a figure of nine per cent.

Spokesman for the CPRE Wiltshire branch Ben Kerwood said: "The effects of intrusion in Wiltshire are considerable, and appear so drastic because the area has been relatively untouched until now. It's a very real problem.

"Wiltshire County Council seem determined to encourage growth and attract tourists, which is inevitably going to affect noise and visual intrusion."

But Wiltshire county councillor Toby Sturgis was cautious over the CPRE's claims.

He said: "It's very difficult to know what the CPRE are calling countryside as in terms of government speak most of Wiltshire is countryside.

"The M4 runs right past the bottom of my farm, but I'd consider myself to be living in the countryside."

Mr Sturgis was adamant that recent development has been in areas outlined by the Regional Spatial Strategy, such as Chippenham. He added: "This is all rather conflicting with what the CPRE says."

Other countryside campaign groups believe the CPRE's report can be useful for conservation work.

Spokesman for Natural England Paul Wynne pointed to the importance of assessment and planning in development.

He said: "The CPRE's work can be put in the pot with everything else. We always urge local authorities to do rigorous assessments, and provide support and advice for them."

And Delly Everard, director of the Countryside Alliance in the South West, said: "As desperate as people are to live and work in the area they come from, no-one wants to encourage widespread development across the countryside."

The CPRE marks areas close to motorways, large towns, power stations and airports as being disturbed by the spread of development.

Places within half a kilometre of A roads, settlements of 2,500 people, mainline railways and power lines also come under the criteria.