One day last summer, Jake Fiennes was lost in a cloud of butterflies. He was on a woodland path near Holkham Beach, on the north coast of Norfolk. Every decade or so, ten million painted-lady butterflies, which are orange, black, and white, migrate to Britain from tropical Africa. The hot summer meant that it was a bumper year for native species, too, and the painted ladies mingled with red admirals, peacocks, and common blues, feeding on bushes set back a few yards from the path. “Just sat in a haze of flittering, fluttering butterflies,” Fiennes told me later. “I was in awe. These flowers were just exploding.”

Two friends of mine happened to be passing at that moment. They saw a figure in the swirl. Fiennes, who is forty-nine, has bright-blue eyes and a shaved head, except for an irregular flap of white hair, which is jagged with gray. He is an arresting presence, with an abrupt, avid way of speaking. He combines the correct jargon of the English countryside—hedges are flailed, ditches are grubbed, the grass is the sward—with a lot of swearing. He starts sentences in the middle. He began to talk to my friends, at them, about the painted ladies, about how they floated on gusts from the Atlas Mountains; how if you looked closely enough you could see the faded wings of the older creatures; and how they got tired flying over the sea, and sometimes rested, like a settling of dusty stars, on fishing boats in the English Channel. My friends stood and gawped for a while. Then they carried on, leaving the butterfly man behind.

Fiennes is the conservation manager of the Holkham Estate, one of Britain’s most important private landholdings. The estate covers about twenty-five thousand acres and includes a nature reserve, which is visited by almost a million people a year, and a farming business that grows potatoes, sugar beets, and barley, for beer. In 2018, Fiennes was hired by Holkham’s principal landowner, the eighth Earl of Leicester, to bolster wildlife across the estate, from its intensively farmed arable land to its wetland bird habitats. Fiennes describes what he does as “multifunctional farming” or “environmental farming.” He believes that farmers in the twenty-first century must cultivate as much as they can on their land—fungi for the soil, grasses for the pollinators, weeds for the insects, insects for the birds, pasture for the livestock—for the long-term goals of carbon capture and food production. “How do we feed the nine billion?” Fiennes said. “We feed them through functioning ecosystems.”

Fiennes has spent his adult life in British farming, but he is not quite of it. He is the twin brother of the actor Joseph Fiennes, and one of six siblings in one of Britain’s best-known bohemian families—the Twisleton-Wykeham-Fiennes, who choose to simplify their surname. (Jake’s eldest brother is Ralph; his sisters, Sophie and Martha, are filmmakers; his third brother, Magnus, is a music producer, based in Los Angeles; Ranulph Fiennes, the polar explorer, is a cousin.) Fiennes is profoundly dyslexic and almost entirely self-taught. Last year, he was an adviser to Britain’s first major review of its national parks since 1947, which was chaired by Julian Glover, a journalist and a former speechwriter for David Cameron. “There’s an element of Jake which looks like he could have taken up farming or heroin,” Glover told me. “There’s no one else quite like him.”

Fiennes lives in an old blacksmith’s house with his partner, Barbara Linsley, an agricultural historian, in the village of Burnham Thorpe, a few miles from Holkham. On the wall above his stairs are the heads and antlers of Britain’s six deer species, which Fiennes has shot and eaten. On a beautiful afternoon last September, Fiennes drove me from his house to the grounds of Holkham Hall, which was built by the Coke family, who were ennobled as the Earls of Leicester by King George II, in 1744. (The name is pronounced “Cook.”) Fiennes turned his Ford Ranger to face the gates and the arrow-straight drive leading into the park, and rolled a black cigarette. “This is the front door of Holkham,” he said. “This is Coke of Norfolk saying, ‘This is how big my cock is.’ ”

Holkham was one of the birthplaces of the agricultural revolution. At the beginning of the nineteenth century, the estate, which included some seventy farms, set new standards for food production, instituting regular four-course crop rotations, long-term leases, systematic breeding programs, and the use of cover crops, such as clover, which fix nitrogen in the soil. Though many of these techniques originated earlier, they were publicized to great effect by Thomas William Coke, a prominent politician. Coke of Norfolk, as he was known, staged annual sheep shearings that drew hundreds of landowners to the estate. In July, 1820, Prince Potemkin of Russia, along with visitors from Baltimore and Paris, learned about Arabian sheep, tricks to stop mice from eating cornstalks, and the correct direction for drilling seeds (north to south). The “Norfolk rotation” was replicated across Britain’s lowland farms and increased food production, liberating workers from the land to take their chances in the mines and factories of the industrial revolution.

When Coke died, in 1842, a stone column with a wheat sheaf on top was erected at Holkham. Fiennes drove his truck across the grass to show it to me. The pedestal is decorated with sculptures of sheep, seed drills, and sayings apposite for our frightening ecological age. “What I love is this,” Fiennes said, pointing at an inscription below a plow. It read “Live and Let Live.”

Fiennes told me to close my eyes. The monument stands in a corner of Jane Austen-style parkland, a dreamlike England. “What can you hear?” Fiennes asked. I was struck by the silence. After a moment, I could make out the small sound of a couple of birds, singing in the distance. “Generally, not a lot,” he said. During Fiennes’s lifetime, Britain has lost about forty-four million breeding birds. “This has become a natural, day-to-day thing that is not there,” Fiennes said. “This is what it is.”

The United Kingdom is a farmed country. Almost seventy-five per cent of the land is given over to agriculture—compared with some forty-five per cent in the United States. After the privations of the Second World War, the country joined a continent-wide push to banish hunger from Europe. Between 1935 and 1998, aided by chemicals, subsidies, heavy machinery, and crop science, British farmers more or less tripled their per-acre yields of wheat, oats, and barley. Milk production doubled. The amount of chicken meat offered for sale increased by a factor of twenty-five. Traditional farming methods, such as the Norfolk rotation, fell away.

Many seminatural habitats were drained or plowed under. An estimated ninety-seven per cent of hay meadows were lost. Between 1990 and 2010, the area of crops treated with pesticides in the U.K. increased by fifty per cent. The environmental damage caused by Britain’s intensive agriculture has only recently been properly understood. In 2013, twenty-five nature organizations published the first “State of Nature” report. “Even the most casual of observers may have noticed that all is not well,” Sir David Attenborough wrote in the foreword.