Beavers could be successfully reintroduced in many parts of England, a conservation body has argued.
Natural England says a study has shown beavers, already set for reintroduction in Scotland, could boost wildlife and reduce flooding, among other benefits.
It is now up to wildlife charities and other groups to decide whether they would like to embark on such a scheme.
Farmers say landowners' concerns must be taken into account. Beavers were hunted to extinction in the 1500s.
'Ecosystem engineers'
They were prized for their fur, their meat and their scent glands, which were used for pain-relieving medicine.
A planned reintroduction of beavers is set to take place in Scotland later this year and a feasibility study is being carried out in Wales.
The creatures have already been successfully reintroduced in parts of Europe and the feasibility study for Natural England, which advises the government on conservation issues, and the People's Trust for Endangered Species said reintroduction could be possible in many parts of England.
Professor John Gurnell, one of the report's authors, said beavers acted as "ecosystem engineers" and could provide many benefits.
BEAVER FACTS

• Beavers are the largest rodent native to Europe with adults weighing 18-20kg and body length of up to 1m
• They are mainly nocturnal eating a very wide range of plants and tree bark -especially willow
• The creatures usually live for seven or eight years but have been known to live for up to 25 years
• They prefer burrows in river banks as their nesting place but will build lodges of piled logs when this is not possible

They sometimes build dams to stabilise the water levels around their burrows and channels for foraging, which can slow rivers and control flooding, purify water and increase the number of plant and animal species in the habitat.
Prof Gurnell said: "The potential for them to give benefits to the country at large is quite enormous. They can boost water quality, alleviate the effects of flooding and raise river levels during drought."
He said some people feared beavers would cause damage to crops, trees or fishponds, spread disease, damage angling or affect wildlife.
But he said "most negative effects are probably more minor than major", limited to some damage to smaller trees, streams and fish ponds, which could be easily dealt with.
He added there was no evidence beavers spread disease.
'Exit strategy'
Natural England has received no requests for a reintroduction scheme.
It said any project would take several years to come to fruition and local communities would need to be consulted before beavers returned to English waterways.
"The plan must include a clear idea of any long-term potential economic and physical impacts on the English landscape, including flood risk or potential for disease transmission"
National Farmers' Union


Natural England's chief scientist, Tom Tew, said: "Beavers could have a range of environment benefits but could only be introduced under the right conditions."
Although beavers are not "aquatic rats" and would not breed quickly, any scheme would also need an "exit strategy" , he added.
Andrea Graham, from the National Farmers' Union, said the costs of reintroducing the species would need to be carefully considered.
"The plan must include a clear idea of any long-term potential economic and physical impacts on the English landscape, including flood risk or, crucially, any potential for disease transmission which becomes more relevant as new and emerging exotic diseases continue to threaten our native animals and wildlife," she said.
The costs of reintroduction seemed a "costly luxury" in the current economic climate, she addedThis article is from the BBC News website. © British Broadcasting Corporation