A major new campaign has been launched to "rewild" Britain, bringing wolves, lynx and even giant sturgeon fish back to Scotland.

An alliance of green charities and public bodies aim to return just a twentieth of the island to its natural state, with hills reforested, rivers clean and lost species repopulated.

A new charity, called Rewilding Britain, will champion the campaign, which will have a heavy focus on Scotland's Highland and lowland wildernesses, the UK's cleanest regions.

Campaigners, who include serious organisations such as the Forestry Commission, Cairngorms National Park and John Muir Trust, stress headline policies such as re-introducing wolves are only part of a bigger picture.

But the National Farmers Union immediately warned of what it called "reckless" schemes to bring back predators and called on Scottish Natural Heritage to "show stronger leadership" on the issue.

Meanwhile, Environment Minister Aileen McLeod is currently deciding on a separate scheme to re-introduce beavers, another initiative opposed by farmers.

Rewilding Britain said species it wanted to see return include beavers, but also wild boar, bison, cranes, dalmatian pelicans, sturgeon, bluefin tuna, lynx and eventually wolves, grey whales, humpbacks and sperm whales.

It wants to see at least three core areas of rewilded land by 2030, which means, in each case, 100,000 hectares or more, with a clear focus on Scotland, mostly because the Scottish Government is ahead of its English counterparts in identifying likely areas. Ultimately, in a century, the believe one million hectares returned to their natural state, about 4.5 per cent of the total territory of the island of Britain.

Rebecca Wrigley, programme manager for Rewilding Britain, said: "We hope we can gather a groundswell of support.

"We want to amplify the message that some pioneers have been putting out for decades, and attract new support.

"Rewilding is really for everyone who cares about our future. Our ecosystems need us."

Rewilding has been inspired by environmentalist George Monbiot, he said: "The changes we're calling for would be considered unexceptional almost anywhere else in Europe, where in many countries populations of beavers, boar, lynx and wolves are already recovering rapidly.

"So far the public appetite for change here has had few outlets. We want to change that, and to restore the living world and our relationship with it."

Wolves have recently returned to countries with much higher population densities than Scotland, such as Belgium. However, large animals will not cross the English Channel on their own.

The NFU remains opposes to wolves, which pose no serious danger to humans but have, in other countries, attacked sheep.

Some landowners want wolves to help manage deer populations - the predators prefer the taste of venison to lamb.

But the NFU's Scottish vice president Andrew McCornick stressed the importance of the current "managed" landscape of most of Scotland, with what he called its "mosaic" of biodiversity.

He said: "Farmers are justifiably concerned at what the introduction of predators could mean for their livestock, particularly the many thousands of sheep kept on Scotland's hills and uplands.

"However, new species will also affect Scotland's existing biodiversity and ecosystems. Many farmers and land managers are already working with other Scottish stakeholders on priority Scottish species such as wildcats, capercaillie and red squirrel and protecting and managing existing wildlife habitats."

Wolves are most likely to be brought back to the Highlands, lynx to the Borders. All repopulations need ministerial permission.

Rewilding Britain has the support of the Friends of the Earth, Forestry Commission, Trees for Life, John Muir Trust, Cairngorms National Park, National Trust and The Ecology Trust, among others.