Almost 700 of the endangered rodents, immortalised in Wind in the Willows, will be released in Northumberland - and it's all thanks really to the otter. The biggest reintroduction of water voles in the UK began this week, with 325 voles released into Kielder Forest in Northumberland, and 350 more to follow later in the summer.
Water voles hold a special place in Britain's natural history, providing the model for Ratty, the much-loved character in The Wind in the Willows. But the species has suffered catastrophic declines over several decades, driven by loss of habitat, the pollution of waterways, increased urbanisation, and rampant populations of American mink, originally farmed for their fur but which escaped into the wild and proved a voracious predator on the native vole. More than 90% of the water vole population across the UK has died out, making it the country's fastest declining land mammal.