Wild beavers could be reintroduced across England, if the UK government gives its approval.

The results of a five-year trial in the southwest of the country, where a small family group is now thriving, are currently being examined.

Nobody knows where the beavers came from, but in 2012 they were spotted on the River Otter in Devon. They might have escaped from a wildlife park, but none nearby were missing any of their animals. It is more likely that they were deliberately released by someone who wanted to reintroduce a species that was hunted to extinction in England about 400 years ago.

Steve Hussey from the Devon Wildlife Trust is one of several experts involved in the long-running scheme.

"The general consensus, it's not unanimous, is that beavers are popular here," says Hussey. "People like to have their local beaver population. It brings in tourists. People, I think for the most part, are quite content they are here on the river. They haven't changed the course of that river or done drastic changes. 

"But there are a minority of people who beavers impact and we have to recognize that, and give them help. That might be financial help, through subsidy, or it might be practical help – education, or we get involved to help manage the beavers locally where they do create problems."

They are cautious, able to stay underwater for 15 minutes and crepuscular (mostly active at twilight) , which means spotting the beavers is not always easy.

But patient visitors can often see the buck-toothed creatures emerge from their lodge to feed after a day inside. The beavers in this part of Devon have successfully bred for several years, but as their numbers grow, so do the potential problems.

In shallower water, beavers build dams. That can alleviate flooding downstream, but creates wetlands in the immediate area. Great for biodiversity, not so great if you are the farmer who loses valuable land.

Sam Bridgewater is the head of wildlife and conservation for the Clinton Devon Estates, which owns the land. He is hopeful that with good management, the future is bright.

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"Beavers like to impound water, generally speaking, humans like to speed it on its way out to sea," says Bridgewater. "And so there have been a couple of cases where that has caused a bit of conflict, nothing too drastic. But, yes, there has been some agricultural land that has flooded.

"I don't think there's any doubt that beavers can do some amazing things, it's how we approach those pinch points, where actually they come into conflict."

In Scotland, there has been fierce opposition from some farmers who believe the reintroduction of beavers there has not been well managed.

Those involved in the English project hope the government will approve a carefully planned reintroduction of this once-native species.

It comes at a time when schemes to reintroduce pine martens, lynx and even bison are being proposed in areas where they haven't been seen for hundreds of years.