The beaver's penchant for hydrological engineering has brought it into conflict with people across Europe and North America for centuries, so it's no small irony that experts are now realising that this is exactly why we need beavers in our countrysides.

"They are the quintessential ecosystem engineers," says ecologist James Byers at the University of New Hampshire. "And they'll do this work for free." Beaver-built waterworks not only create habitats for wildlife, they also boost water quality and reduce the twin threats of drought and flooding. In fact, the beaver could even be an invaluable ally in battling the effects of climate change.

Now re-established in 26 European countries, beavers are missing from only a handful including Italy, Greece, Albania, Macedonia and mainland Britain (there is no evidence that beavers have ever lived in Ireland).

I'm sold on the ecological benefits, and the benefits to biodiversity, not least to water voles and otters,"

UK's Environment Agency