Countryside campaigners warn that rural areas in Norfolk and Suffolk are being swallowed up by urban blight faster than the national average. The relentless intrusion into the countryside could mean that areas free from major disturbance could all but disappear in most regions of England well before the end of the century.

Countryside campaigners warn that rural areas in Norfolk and Suffolk are being swallowed up by urban blight faster than the national average.

The relentless intrusion into the countryside could mean that areas free from major disturbance could all but disappear in most regions of England well before the end of the century.

And startling new maps, published by the Campaign to Protect Rural England (CPRE), show that the East has lost another 840 sq miles - an area equivalent to half the size of Suffolk - to disturbance from noise and visual intrusion since the 1990s.

At current rates of loss much of the region's remaining countryside could be blighted in just 70 years.

Shaun Spiers, CPRE chief executive, said: "Countryside which is undisturbed by noise and development is vital for our quality of life and well-being. These maps show what the future may hold if we don't sufficiently value our wonderful rural landscapes. As the shadow of intrusion stretches further and wider, the peace and quiet we need is harder to find."

The new research brings together maps for the early 1960s and 1990s with new maps and data for 2007.

They show the extent of urban intrusion, including major infrastructure such as motorways, power stations, and airports.

The east of England is one of England's fastest growing and fastest changing regions. Once quieter with broad stretches of undisturbed countryside, it is now the third most disturbed by noise and visual intrusion.

While Norfolk, Suffolk and Essex have significant reserves of undisturbed countryside, the research shows all have suffered more loss

than the national average since the 1990s.

The maps show the intrusion of the A1067 in west Norfolk, together with more black spots representing what is now considered urban areas compared with the 1990s.

North Walsham and Aylsham are also black spots denoting urban sprawl for the first time which has also extended on the coast.

Mr Spiers added: "The findings of this research are a wake-up call for the government. It must strengthen policy to protect the remaining areas of undisturbed land and protect it for future generations."

The maps show that in the early 1960s, 26pc of England's land area was disturbed by urban intrusion; in the early 1990s, this had grown to 41pc; and by 2007, 50pc of England was affected by urban intrusion. CPRE is calling for stronger policies from government, including: more ambitious targets for recycling brownfield land, promoting public transport as an attractive alternative to the car and halting current airport expansion plans.