But now after a five-year environmental assessment, the Government has ruled the beavers - now numbering 15 family groups - can stay for good and expand their range naturally.
James Wallace, director of the Beaver Trust, said: 'Having shown through research and community engagement numerous benefits, challenges and ways of living alongside beavers, it is time to apply the learning from the River Otter Beaver Trial across the rest of the country'.
Devon Wildlife Trust's Mark Elliott said it was now vital for a national plan on the beavers' future as well as help for landowners adversely affected. They will be launching a consultation into the reintroduction of formerly native animals later this year. "But we also understand that there are implications for landowners, and take care to ensure that all potential impacts are carefully considered, and today we can confirm a new government consultation on our national approach and management will open later this year".
The five-year trial run by the DWT and licensed by Natural England ends on 31 August 2020.
There are believed to be other beavers living on English rivers after having escaped or being released, and there are calls to help these populations too.
Wildlife experts still want more doing across the United Kingdom though to help different beaver populations, so the number of them can keep on growing, and so they can return to other rivers to create wetlands, boost wildlife, reduce flooding and improve water quality.
He explained: "Reintroductions of iconic species like the beaver will be an important part of the Nature Recovery Network".
"This is the most groundbreaking government decision for England's wildlife for a generation", said Peter Burgess, Director of Conservation at Devon Wildlife Trust. Beavers are nature's engineers and have the unrivalled ability to breathe new life into our rivers.
England's first wild beaver colony to live on a river for 400 years will not be evicted after the Government said it was eager for them to stay.
"We are firmly committed to providing opportunities to reintroduce formerly native species, such as beavers, where the benefits for the environment, people and the economy are clear". In that time their population has grown steadily so that they have successfully colonised almost all of the river's catchment. We're delighted that these beavers have now been given leave to stay permanently.
Beavers, semi-aquatic vegetarian mammals, were hunted to extinction in Britain more than four centuries ago because people wanted their meat, fur and castoreum, a secretion that was used in medicine and perfumes.