The Konik stallions are having a bit of a dust-up in the distance, but the Highland cattle keep their heads down in the grass, ignoring the flying hooves. Around nine species of bird can be seen feasting on the hawthorn flies and tiny fish rising to the top of the sparkling lode.

This is Wicken Fen, a 760-hectare haven surrounded by Cambridgeshire farmland, which could become much bigger: the National Trust’s ambitious 100-year plan for the marshland site is to expand to 5,300 hectares. The site has already doubled in size since the start, in 1999, of a project to reclaim ploughed and drained farmland and let it revert to fen.

The reintroduced species are herds of feral cattle and wild horses, rather than the more eye-catching wolves and bears being suggested for other parts of the UK, but Wicken Fen is still among the most ambitious of the UK’s “rewilding” projects.

Facebook Twitter Pinterest Konik horses on Wicken Fen. Photograph: /Robinson/Rex Shutterstock

“The idea is not to preserve the landscape in aspic,” said its countryside manager, Martin Lester, “but to create an ecology that is dynamic and changing and will build up natural resources to cope with things like climate change. It’s called rewilding but it’s not wilderness; it’s more like renaturing.”

This year marks a major ramping-up of Britain’s rewilding schemes, according to Simon Jones, director of conservation at the Scottish Wildlife Trust. The charity is about to report on the trial reintroduction of a beaver colony to Tayside, and is hoping the Scottish government will let the animals stay.

“We’re definitely seeing this grab the public imagination. And the beavers are the flagship species for that,” he says. “It was a big deal to bring the beavers here, and it’s also a sign that society can take bolder steps with restoring our eco-systems.

“Better diversity is better for our environment – as the beavers have proven. We’re learning that you can’t just point to an enclosed place on a map and say that’s where our wildlife is. It’s really about the management challenges – where people go for help if they have problems. We’ve learned that it’s important to have everyone round the table to debate the issues.”

Facebook Twitter Pinterest Lynx could soon be introduced at several British sites. Photograph: Alamy

Applications are being submitted this month to Natural England and Scottish National Heritage for a five-year trial to release around 18 lynxes at sites in Norfolk, Cumbria, Northumberland and Aberdeenshire. The predators have not been here for more than 1,200 years. The animals would be brought over from Europe by the end of this year, according to the Lynx UK Trust, which says surveys suggest 90% of the public is in favour of the plan, although support was 5% lower in rural communities.

The main argument against the reintroduction of lynxes, wolves and bears is the safety of livestock, especially sheep. But Paul O’Donoghue, chief scientific adviser to the Lynx UK Trust, which has been working on the reintroduction plans for more than two years, is quick to insist that lynxes are not significant sheep predators.

Dozens of more modest projects are taking place on private land, and some farmers are also attempting to move towards nature-sensitive farming. But with land under pressure from all directions – housing, industry and food production – it’s an uphill battle.

At Knepp Castle Estate in West Sussex, rare native black poplars have been planted and a canalised river is being renaturalised. In Scotland, charity Trees for Life has planted 1.2 million trees, mostly Scots pine, and plans to have planted two million before the end of the decade.

At the Alladale Wilderness Reserve in the Scottish Highlands, owner Paul Lister has caused controversy with neighbours and ramblers by bringing in elks and wild boars; he is planning to introduce wolves and bears. His replanted forests are threatened by the large numbers of deer which, he argues, need to be controlled by bringing back Britain’s predators. He adds that wolves, as well as eating deer, would also be a tourist attraction, bringing in money to the area. The reintroduction of white-tailed sea eagles on Mull is estimated to have increased the island’s tourist industry by £5m a year.

Facebook Twitter Pinterest Some say wolves should be introduced to control deer numbers in parts of Scotland. Photograph: Alamy

But rewilding has its sceptics. Simon Fairlie, a farmer and ecologist living in Dorset, has written a book about sustainable meat eating and edits the magazine The Land. “What worries me,” he says, “is that some of the rewilding is on prime agricultural land, grade one. Land in the Fens was drained at great expense to produce food and now it’s being undrained at great expense. Meanwhile, our self-sufficiency in food production is dropping: it’s gone from 70% to about 60% in the past few years. We’re even importing milk.”

Fairlie believes in the need for more biodiversity, but says enthusiasm for a return to past landscapes might go too far while as a nation we can’t feed ourselves from the land.

“The whole emphasis of European funding has switched: the pendulum has swung from 15 years ago when it was all ‘produce, produce, produce’ with wine lakes and butter mountains and the rest. Now it’s gone the other way to be all about leaving the land alone. It’s a golden ticket for big landowners. Now you’re better off not farming dairy cows than farming them, which means that when middle-sized farms go bust the big neighbouring farms snap up the best land and get bigger, and the smaller plots are sold off to horsey types or smallholders.”

He says he agrees with the science behind reforesting uplands, to help with flooding and soil erosion, but points out: “It doesn’t need to be a complete rewilding, just a few patches or shelter belts.”

At Wicken Fen, sitting on a rough-hewn oak bench, Martin Lester has been chatting to a cheery birdwatcher who tells him that this is his favourite spot, where the birdsong is at its most exquisite. The pair reel off a list of species: redshanks and lapwings, egrets, grasshopper warblers and herons.

As the man heads off in search of a bittern, Lester remarks that the value of a place like this is beyond measure: “Wicken isn’t a wilderness by any stretch, but everyone has a favourite spot where the big skies, the wind in the reeds and the wildlife make then feel as if for a moment they are at one with wildness.”

But he acknowledges Fairlie’s point: “The food thing is levelled at us – we’re acutely aware of that. But our project takes up about 1% of the food-producing land in the Fens. And remember that a third of the food we buy ends up in the bin, and that even before it reaches our fridges the supermarkets have rejected a lot more because of the way it looks. Then you can start to put things in perspective.

“If there was a national emergency, this land could go back to arable easily. I look at where we were 15 years ago and it’s gratifying to see the way our very meagre ambitions have succeeded beyond our wildest dreams – with just a little bit of imagination and patience, and not a lot of money.

“But,” he adds wistfully, “wouldn’t it be great to have a lynx or two here?”

WHERE THE WILD THINGS ARE

Reindeer Around since the stone age, reindeer were reintroduced in 1952, and now a 150-strong herd lives wild in the Cairngorm mountains of Scotland.

Facebook Twitter Pinterest Black grouse. Photograph: /James Shooter / Rex Features

Black grouse Having disappeared from the north of England in 2000, black grouse were reintroduced to Derbyshire in 2003 and the population is flourishing. Wild horses Britain has numerous herds of feral horses, mostly descended from domesticated horses which were allowed to roam semi-wild. Koniks, descendants of wild European tarpan horses, are the latest immigrants (from the Netherlands). Existing herds include the Dartmoor, Exmoor, Welsh mountain and Highland ponies.

Wild boars A once-flourishing population was slaughtered to zero in the 13th century. An attempt to reintroduce them in the 17th century failed. There are now thought to be around eight small breeding herds running wild in the south of England, Wales and Scotland, mainly established by escapees from farms.