The Isles of Scilly is the third most unspoilt county in England, a survey has revealed.

Just 26% of land on the Islands is disturbed by buildings, transport and noise.

A ‘tranquillity map’ compiled by the Campaign to Protect Rural England shows that more than half of the country is affected by nearby roads, towns, pylons, aircraft and trains.

The map does not include areas within two-and-a-half miles of a power station, two miles from large roads or towns, or half a mile from a main railway line.

Northumberland is the most unspoilt county with 17% of land disturbed, followed by Herefordshire with 21%.

The charity warns that the last remaining tranquil areas may disappear by the end of the century if the current trend continues.

CPRE chief executive Shaun Spiers told the Daily Mail: “The findings are a wake-up call for the Government. The impact of development spreads way beyond its immediate footprint. More must be done to protect what is left from further fragmentation.”

In the early 1960s, 26% of England was disturbed by the sight and sound of urban development, growing to 41% by the 1990s and to about 50% by this year.