Climate changes have increased risks of flooding

The land involved in the project was reclaimed from the Tamar 150 years ago for agriculture. Now it is to be returned to the river.

Three breaches will be created in the embankment to allow the waters of the Tamar to flood in.

The flooded area will become a mud flat and then, after about 20 years, an extensive reed bed.

Reeds are important for rare species like the otter. They are relatively scarce in Britain, with many being lost to farming or development.

Climate change

Brian Muelaner of the National Trust said: "We'll have a very rich and diverse flora, with reed buntings, various warblers, lots of birds and lots of amphibians.

"Hopefully, we can also bring back the water vole, which sadly seems to be very scarce at the moment."

Climate change has led to stormier weather, and an increased risk of flooding.

The managed retreat will help alleviate this by providing more areas for rivers to overflow without damaging property.

Marine habitats

Dr Tony Stebbing from the Centre for Climate Change Impact Forecasting said: "We're going to see far more habitats released to the marine environment, as it were, in the future.

"This is simply because the cost of protecting them is going to be greater than the value of the land itself."

The land is due to be flooded in June 2002.

The National Trust said access to the Cotehele estate will be unaffected, as it plans to put in a walkway.