The British government is considering plans to release beavers back into the wild across England about four centuries after the dam-building mammals became extinct in the country. The proposals, a cautious step towards establishing a native beaver population, would see the animals reintroduced if strict criteria were met, along with an assessment of their impact on the land and other species. It comes after a successful five-year trial on the Otter River in Devon, south-west England, concluded that a family of beavers had a beneficial effect on the local ecology. It was the first legally sanctioned reintroduction to England of an extinct native mammal. "Today marks a significant milestone for the reintroduction of beavers in the wild," Environment Minister George Eustice said on Tuesday, at the start of a 12-week consultation on the plans. "But we also understand that there are implications for landowners so we are taking a cautious approach to ensure that all potential impacts are carefully considered." The government said beavers could play a hugely significant role in helping to restore nature, creating dams from trees, mud and rocks, which raise water levels and create wetland habitats that support the recovery of a wide range of native species. The semi-aquatic vegetarian mammals were hunted to extinction in Britain about 400 years ago for their meat, fur and castoreum, a secretion that was used in medicine and perfumes. The government said it also planned to make it an offence to capture, kill, disturb or injure beavers, or damage their breeding sites.