Everything that has gone wrong with conservation is exemplified by this decision: the cowardice, the grovelling, the blandishments, the falsehoods. The way conservation groups rolled over is shameful, but also familiar. They did nothing to prevent the Lake District, England’s largest and most spectacular national park, from being officially designated a Beatrix Potter-themed sheep museum.

On Sunday, the UN agency Unesco granted the Lake District world heritage status. This, according to the report on which the decision was based, will correct an “imbalance” between “natural values” and “the cultural values of farming practices”.

The entire high fells have been reduced by sheep to a treeless waste of cropped turf whose monotony is relieved only by erosion gullies, exposed soil and bare rock. Almost all the bird, mammal and insect species you might expect to find in a national park are suppressed or absent, and 75% of wildlife sites are in an unfavourable condition. So you could be forgiven for thinking that the balance should be tilted back towards nature. Oh no: apparently it’s “the cultural values and benefits of the farming activities” that have been neglected.

Given that sheep-worship is the official religion in the Lake District, and that sheep exist here only because of lashings of public money (hill farming is sustained entirely through subsidies), it’s not easy to see what more can be done. But world heritage status will make attempts to defend our natural heritage much harder. It will be used to block efforts to reduce grazing pressure, protect the soil and bring back trees.

The Lake District’s new designation is based on a fairytale with great cultural power. For 3,000 years this story has presented sheep farming as the seat of innocence and purity; an Arcadian refuge from the corruption of the city, an idyll in perfect harmony with the natural world.

The reality couldn’t be more different. Sheep farming is now characterised by land consolidation, subsidy harvesting, ranching on a scale that looks more like Argentina than anything Wordsworth would have recognised, quad bikes, steel barns and absentee ownership. But the myths persist, and they blind us to some brutal realities.

Sheep, by nibbling out tree seedlings and other edible species, are a fully automated system for ecological destruction. They cleanse the land of almost all wildlife. In the UK they occupy some 4m hectares of our uplands. Compare this to the built environment (houses, factories, offices, roads, railways, airports, even parks and gardens) that covers 1.7m hectares. Yet this vast area, which is roughly equivalent to all our arable land, produces around 1.2% of our food (probably a good deal less, as the figure includes lamb from lowland farms). Our infertile uplands, including most of our national parks, would be better used to protect and restore the wonders of the living world. If we are to spend £3bn a year of public money, it should be deployed for ecological restoration rather than destruction. But the cultural power of this industry is so great that hardly anyone dares challenge it.

In trying to contest the bid for world heritage status, I found myself almost alone: only a handful of independent ecologists spoke out. Privately, major conservation groups might have expressed misgivings, but in public they not only failed to oppose this attack on everything they claim to defend: they actually put their names to it. The National Trust, the RSPB, the Lake District national park authority and Cumbria Wildlife Trust are members of the partnership that petitioned for world heritage status. These turkeys not only voted for Christmas; they canvassed for it.

It’s not hard to see why. There’s a tangible atmosphere of fear in the Lake District: any environmental group that speaks out knows it will be Thorneythwaited. In other words, it will be treated as the National Trust was when it bought a farm at Thorneythwaite, in Borrowdale, without the farmhouse. This seeded the suspicion (sadly baseless) that it intended to remove the sheep.

If there was a fault, it surely lay with the seller, who had split the house from the land, rather than the buyer. But the national media, taking its cue from the sheep farmers it fetishises, subscribed to this concocted controversy and lambasted the National Trust. Its chastisement stands as a ghastly warning to anyone who questions the holy cult. But appeasement only empowers your opponents. What makes the collaboration of these groups so grisly is that the British conservation movement began in the Lake District. It is here that the circle has been closed, with the comprehensive betrayal of its own legacy.

The Lake District partnership commissioned its economic evaluation from a company called Rebanks Consulting. It is owned and run by James Rebanks, a Lake District sheep farmer. He was paid £30,000, in effect, to promote his own industry’s interests. The bid was riddled with errors and omissions: the claim that the park is in “good physical condition”, that the relationship between sheep and wildlife is “harmonious”, that farming there is “wholly authentic in terms of … its traditions, techniques and management systems”. Leaving the European Union – on which, through subsidies, sheep farming is wholly reliant – wasn’t mentioned.

These fables passed unchallenged into Unesco’s own report. Some were even compounded: Unesco’s consultants claimed that while overgrazing damaged wildlife “in the past”, it has now been “corrected”. It doesn’t say how, because no such thing has occurred. Even the bid documents acknowledged that sheep numbers in the Lake District have risen by 9% in four years, leading to “issues such as overgrazing”.

I tried to warn Unesco, but everyone I wrote to passed the buck to someone else (on my website I detail the comical ways in which I was fobbed off). I discovered that accountability, transparency and public engagement are alien concepts: Unesco is a black box. Without the support of NGOs, my efforts were bound to fail. Groups such as the National Trust, the RSPB and the Wildlife Trusts publish pungent reports documenting the rapid loss of wildlife and ecosystems, but they have failed to mobilise their vast memberships in defence of the living world. On the contrary, they bamboozle their members through their display boards and pamphlets, describing devastated landscapes as “wild” and “unspoilt”, and even celebrating cutting, burning and grazing, which are the major causes of environmental destruction.

The culture of deference in the countryside afflicts almost everyone. Those who own and farm the land are treated as heroes, while anyone who challenges them is denounced as an “extremist”: this is what Eric Robson, who presents Gardeners’ Question Time on Radio 4, called me on Monday, for raising objections. Our national parks are wiped clean, our natural heritage erased for the sake of an ersatz farm fantasy. And there is nowhere to turn.