The farmer who wouldn't cow-tow: Rather than supply supermarkets and face financial ruin, Steve Hook has developed a market for 'raw' milks

What if there were a simple cure for some of life's most common afflictions, such as eczema, asthma, or hay fever? Something that's natural, relatively inexpensive and that most people drink every single day. Now imagine this miracle salvation, which has sustained generations of children on farms across Britain, is at best tricky to source, and at worst illegal.

The sale of unpasteurised milk, which is already prohibited in Scotland, could be banned in England and Wales when the Food Standards Agency (FSA) unveils the results of its 15-month review into the booming market for "raw" milk later this summer.

That is the nightmare scenario for farmers such as Steve Hook, who has transformed the fortunes of his family farm since he started selling raw milk six years ago, if the FSA is swayed by some of the biggest voices in Mr Hook's industry, including the lobbying group Dairy UK.

A new film out this week will reveal the lengths that Mr Hook has gone to in his quest to keep his East Sussex farm afloat despite operating in a market where consumers often pay less for a product than it costs to produce. This leaves many farmers reliant on state handouts. "It's fundamentally wrong because it means the taxpayer is paying for the farmer's living. Indirectly, the taxpayer is subsidising the supermarket, which is making a profit out of its milk because it's paying so little," Mr Hook says.

Rather than play the supermarkets' game, one in which "the moment milk is pasteurised it turns into a commodity", Mr Hook has gone it alone, selling his raw version straight from the cow's udders to the consumer. The 12 pints he delivered out of the back of his Volvo to a handful of residents of nearby Hailsham in January 2007 have grown to 4,000 pints a week, which he sells across the UK via the internet. He had to do this because FSA controls only permit the sale of raw cows' milk directly from the farm where it is produced, something Mr Hook thinks is "fantastic. There's no middle man, no end seller, just me, which gives me control over my price. Plus it's great to sell a product you believe in." (He gets away with selling it online because the computer doing the transaction is based on his farm.)

He's subject to strict controls, of course: his milk, which carries a cigarette-style health warning, must pass stringent health checks, such are the potential risks. Mr Hook goes the extra mile, testing weekly for a plethora of pathogens. "The worst thing would be a food scare. That would be our brand and raw milk down the pan," he says. His 70-strong herd is also free of tuberculosis.

For all that the softly spoken Mr Hook is passionate about raw milk, The Moo Man, which wowed the Sundance Film Festival in January, is no campaigning diatribe. It follows Mr Hook and his family, from his father Phil down to his chihuahua Tinky, as they expand the business. This includes taking his favourite cow, Ida, to Eastbourne for a photo-shoot.

As in life, so on film; it's the cows that are the real stars: Mr Hook stands in a field, picking out some of the bovine celebrities to introduce me to. "There's Kitty; she's on the cover of the DVD. She doesn't take any nonsense, not even from the herd bully, Biddy. 'You're the boss, even though you're young, aren't you?'" he says, stroking her neck. "And Ration, she's our red carpet cow," he gestures to another.

Mr Hook hopes the film will help the public to "re-engage with where their food comes from". He adds: "People say afterwards that they'll never look at milk the same way again. We're in danger of losing our respect for food, which means it very quickly becomes a waste product." At anything from £1.50 to £2.50 per pint, depending on whether you buy it at one of the farmers' markets Mr Hook attends or from a far-flung corner of England, there is plenty of incentive not to waste his product. Contrast that with the 32p per pint Tesco charges if you buy it four pints at a time.

It's what Mr Hook regards as the benefits that mean people don't mind paying his prices. "There are only two similarities: they're both white, and they're both called milk," he says of raw versus pasteurised. "It was when a guy made a 120-mile round trip one New Year's Eve to buy 20 pints that I realised raw milk wasn't a commodity," he adds. Fans believe it can get rid of asthma, eczema and hay fever, as well as lower cholesterol. Research has also implied that it helps to reduce children's chances of developing allergies. The theory behind all this is that pasteurisation, which heats milk to 71C for 15 seconds, destroys good as well as bad bacteria.

And those risks? Well, the FSA's food policy expert, Bindiya Shah, admits that the watchdog could not find any outbreaks of food poisoning linked to drinking raw milk in England or Wales during the past 10 years. That said, Jenny Morris, who headed the Chartered Institute of Environmental Health's food safety team at the Olympics, insists those figures "might not be the whole picture. There are no indications yet that all the risks have gone away," she added.

Mr Hook, and the 100 or so other farmers also selling raw milk in England and Wales, must just wait and hope that the FSA is happy to let the customers carry on weighing up those risks.

The Moo Man is released on Thursday at selected cinemas nationwide. See the-mooman.co.uk