The National Trust is planning to buy and flood 14 square miles of top-grade farmland in a giant scheme to save hundreds of threatened plants and animals. The project will transform bleak and intensively cultivated fenland into a vast wetland nature reserve.
The heart of the scheme is 800-acre Wicken Fen, which supports more wildlife than nearly anywhere else in Britain. Most of the land around Wicken is below sea level, prone to flooding and sparsely populated. Farming is viable only with constant pumping. If the trust's executive confirms the plan, the pumps will be stopped, to extend Wicken's reedbeds and grazing marshes six miles to the outskirts of Cambridge.
Wicken is the country's oldest National Nature Reserve, established a century ago, and served as an outdoor laboratory for generations of Cambridge scientists.
In the early 19th century, Charles Darwin was drawn by a fascination with its 1,000 beetle species. There are exceptional quantities of insects - 212 species of spider, 1,000 of moths, and 1,700 of flies - with many unknown anywhere else.
Adrian Colston, the reserve manager, said: "The average nature reserve in this area is 35 acres but that's hopelessly small. If a cow dungs in the wrong place or someone treads on the wrong spot that can wipe out a vulnerable species."