Home from chasing lost sheep on a beautiful sunlit evening on Exmoor, Robin Milton contemplates the future for his thousand ewes. He is the eighth generation farming this green patch of England, 1,200 feet up, sodden with 80 inches of rain a year on land good for nothing much else. His income is “tiny”, he says. ”But you can’t know the pleasure it gives me, the pride I take in my sheep, the landscape, my hedges and stone walls.”

Brexit casts its shadow across his horizon. “Trepidation” is what he feels. “What have we done? I ask myself half the time.” He voted leave, but says: “I haven’t changed my mind.” He was influenced by his son, who thought ending EU subsidy would see agricultural land prices fall, so the young could get into farming. Is that likely? Farmland prices rose 149% over the past 10 years, according to the property company Savils, as rich investors backed land in uncertain times.

He is full of fears, but holds firm to his vote – one of the 58% of farmers who voted out, but are now alarmed at possible consequences. Read Farmers Weekly to see the perversity when industry is in such peril from Brexit.

An average of 55% of farm income comes from the EU’s reviled common agriculture policy – known as the CAP – and its subsidies. Losing these would cut swaths through agriculture and the landscape. The amount of its food that Britain grows is currently 60% and falling – in a world with ever more insecure food supplies: we are nine meals from empty supermarket shelves. Farming is small but with food processing makes up 13% of GDP, an industry bigger than cars and aerospace put together.

In the referendum Brexiteers offered wildly contradictory promises. Michael Gove, now environment secretary, at the time promised that global trade would bring cheaper food to a Britain out of “protectionist” Europe. But faced with the farmers at the Royal Welsh Show last week, he promised they would keep all their subsidies at least until 2022 – (though no clue for after that). Did they believe him? One commented to Farmers Weekly: “I wouldn’t even put his promise in my muck spreader.”

Dieter Helm, an adviser to Michael Gove’s environment department, has accused farmers of ‘subsidy addiction’. Photograph: Anna Gordon

Farmers had their worst fears confirmed last week when Dieter Helm, an Oxford economist and adviser to Gove’s Department of Environment, Food and Rural Affairs (Defra), accused them of “subsidy addiction” – not just for CAP payments, but their many other perks: tax-free red diesel for their tractors, exemption from rates, and above all no inheritance tax when passing on immensely valuable property. He derided farmers for getting £3bn in subsidies for producing 0.7% of GDP: an output worth just £9bn.

It dawns on farmers that once subsidy is in the Treasury’s hands, not the EU, at every budget they will be competing with the NHS, social care, education, everything else. As revenues fall after Brexit, any chancellor will eye farmers’ benefits.

In Wales Gove promised as “a fact” that the UK would get “a comprehensive free trade deal with the EU”. How can he be sure? Trade matters far more than subsidies for farming. Most meat exports go to the EU, tariff free: hard Brexit on World Trade Organisation rules means a 60% tariff.

Farmers who voted Brexit dreamed of a better subsidy regime than the CAP, a bonfire of paperwork and regulations, leaving them free to do as they please under policies designed just for them, answering their perennial complaints that Britain pays too little for food. Back then they couldn’t have heard Brexiteer promises of cheap food from around the world: now they fear being sold down the river in deals with the US, Brazil and South Africa importing cheap (low regulation) food in exchange for UK services and aerospace. Instead they want a deal with the EU that keeps things exactly as they are. “Without an EU trade deal, all sheep farmers will go bankrupt,” Milton warns.

The dilemmas of farming echo myriad contradictions only now tumbling to earth from the leave campaign’s airy fantasies. For the Conservatives, farmers pose an excruciating problem of existential identity. Tories have been the party of farmers and the shires ever since the great Corn Laws split – yet their wild Brexiteers seek farmer-destroying trade around the world.

Remainers may enjoy a little schadenfreude when Brexit-backing James Dyson, who has invested his billions in English farmland, squeals in pain at the prospect of losing his £1.6m-a-year CAP subsidies. He is now Britain’s biggest farmer and the CAP pays out by the acre. On the one hand, he tells the Spectator, he thinks: “We won’t get an EU deal. We will have to walk away.” But losing subsidy means “cattle farmers will just have to give up”. What did he expect?

Farmers fall back on their role as stewards of the traditional British countryside. Gove suggests switching subsidy more towards environmental protection. But farmers and the environment are often in conflict. Farmers Weekly leads with its petition to repeal a Defra rule forbidding hedge cutting until the end of August: a farmer is suing Defra for this “ridiculous ban” that cost him £24,000 of hedge-cutting contract work. The farmers’ union says only wood pigeons are still nesting, defying a 10-year study by the British Trust for Ornithology that Defra quotes, showing that many species including spotted flycatchers, dunnocks, reed buntings and yellowhammers still nest in August.

Is the Conservative party still the conservator of England’s green and pleasant land, protector of farmers and our rolling dry stone wall landscapes? Theresa May thought so when she put fox hunting in her manifesto. Does little England need to become food self-sufficient in a dangerous climate-changing world? Gove, pledged to preserve our high standards, rejects US chemicalised produce. But are the Tories now transformed into globalised, borderless “nowhere” people, free-trading adventurers bringing cheap food from everywhere – and the devil take food quality, farmers and environment?

The Tory paper the Daily Telegraph is split too. Suddenly it weeps unaccustomed crocodile tears for the “appalling numbers”, the “5.3 million who have trouble putting an adequate amount of food on the table”, when trade with the US for cheaper food can make Britain “less hungry”. Yet this Telegraph is home to Prince Charles-style countryside protection and the roast beef of old England.

It’s hard not to gloat at this mortal split in the party that caused the Brexit crisis, riven by irreconcilable cultural differences. Farmers are right to feel great trepidation over which side wins.