If building a mass market brand from hemp seeds wasn’t challenging enough, try juggling it with a career in Hollywood. Taking a break on set from filming the blockbuster sequel to comic book smash hit Guardians of the Galaxy in sunny LA, part-time farmer and part-time director of photography Henry Braham explains how to squeeze oil, protein powder and milk out of the tiny seed. And it’s the latter he is most excited about.

“Milk is the big story,” he says. “Having realised the potential of hemp, it has taken us some time to understand how to do it in a mainstream food. The new process we have developed in the past two years is all about scaleability for the milk.”

So is everyone on set drinking Good Hemp milk? “Funnily enough they are,” he laughs. “It’s much more common out here than it is in Europe.”

Braham expects to sell more than two million packs of hemp milk in the UK this year (50% more year on year), with retail value of £3m (up 35% from 2015) - plus £1.5m from the oil (up 10%).

Good Hemp has come a long way since 1996, when Braham and wife Glynis Murray, a film and television producer, purchased Collabear Farm - a mustard yellow cottage with a thatched roof tucked away in Devon - with 200 acres of land to grow hemp.

Despite the bucolic setting, complete with two Patterdale Terriers (Boris and Woody), chickens and geese, Murray insists Good Hemp is no cottage industry. “It is a serious business and we have ambitions to grow a brand making all sorts of food,” she says.

Banned in the UK from 1971 to 1993 because of its similarities in appearance to cannabis, today hemp growers still need a licence from the Home Office. The plant, which has literally thousands of uses, is fast-growing (like the business) without need for any pesticides or chemicals.

The first crop ended up in Germany as an eco-alternative for PVC interiors in BMW cars, but then they read about the potential locked inside the seed to produce healthy oil, with 25 times more omega-3 than olive oil, and 40% less saturated fat. “We realised hemp was an incredibly healthy ingredient,” Murray adds. “It wasn’t going to be a fad; it wasn’t going to disappear..

After years of working out how to create the cold-pressed oil (“the secret is drying the seed as soon as it comes off the plant to avoid it going rancid”), Good Oil was born in 2005. A listing with Waitrose followed, as did calls from Tesco and Sainsbury’s, along with praise from Jamie Oliver and Hugh Fearnley-Whittingstall. Former Waitrose CEO Steven Esom came on board in 2011 as a non-exec director to help professionalise the operation.

“We could have just made the oil and we would have been really proud of it, but our ambition is greater than that,” Murray says. “Having worked in the worlds of film and advertising, we were very aware if you want a brand, you can’t just have one product, which is why we moved into the hemp milk.”

Years of trial and error, with false starts and countless batches cooked up in the farmhouse kitchen followed, with the husband-and-wife team investing millions of their own money earned from a career producing commercials for the likes of Walkers, Sharwood’s, Kingsmill and Coke, as well as D&G and Burberry, and films such as Waking Ned, Nanny McPhee and The Golden Compass.

“There are no experts out there for hemp,” Braham says. “If you want to build a dairy plant it’s easy, there is billions of pounds of research to go on. But for hemp it is one thing reading the science and quite another having the experience, and the experience was expensive with lots of disasters. Although having a disaster is a good thing if you learn from it.”

In 2014, Good Hemp received its first injection of external funding from an investor club with form in food (previous investments include wine business Chapel Down and gluten-free brand Genius), which gave the business the capacity to produce milk on a large scale. The £1m manufacturing plant, designed by Braham, is the only one of its kind in the world.

“We have a big advantage over everyone as we know our product and ingredient inside out,” he says. “There is a huge barrier to entry for any potential rivals.”

Unlike the process of crushing the seed to make oil, making milk involves removing the outer shell (“not easy to do as it’s tiny”) to leave a pine nut-like inner seed which is squeezed into a cream and diluted with apple juice. The product, which comes in three varieties (original, unsweetened and coconut) is dairy-free and, like the oil, clean label, gluten-, GM- and allergen-free.

But can the market for hemp milk ever be anything more than niche?

“Maybe 18 months ago we might have agreed, but the whole category is becoming mass market and we are part of that,” says Esom, who has steadily become more involved in the business and has a close working relationship with Braham and Murray. “In two or three years specialty milk will be very mainstream and Good Hemp will be part of that movement.”

“Alpro forged the way and made a market for non-dairy but shoppers are turning away from soya. And people like us are filling those gaps.”

Specialist milk now clocks up £281m in supermarket sales [52 w/e 3 January, Kantar], up 20% year-on-year, with Good Hemp growing at 64%, making it the fastest-growing brand in the category.

The rapid growth is thanks to “incredibly loyal” customers buying more milk per shopping trip, as well as the increasing popularity of unsweetened which is catching up to the original.

“The level of customer loyalty is really unusual,” Braham adds. “If you take the oil story, and it is true of the milk as well, the repeat purchase is almost unheard of because there isn’t anything like it on the market.”

A move into fridges alongside traditional dairy milk in Waitrose and Asda, with the rest to follow, is expected to fuel at least another 50% year-on-year rise in sales with no cannibalisation in ambient anticipated. And with household penetration for hemp milk at just 0.5%, the room for growth is massive, Esom adds.

“Consumers are looking for dairy alternatives in the chiller,” says Esom. “It is a big growth opportunity for retailers and that is good for us. The value of a litre of Good Hemp at £1.60 is clearly ahead of milk so there is opportunity to trade up customers.”

And with more flavours set to be developed and a foray into TV advertising (where the pair have strong form) on the cards, Braham, Murray and Esom are convinced the range can be huge.

The business is cash-hungry, however, with a second £1.5m round of funding from the current investors in the final stages and all profits being swallowed up to fuel the rapid growth.

Up next is a lifestyle brand extension to be launched in April with four basic SKUs (protein shakes, energy balls, energy bars and snacks), which Murray predicts will be equally as big as the milk.

“There is a lot of NPD done, sitting in the cupboard ready to go,” Braham adds. “And the potential is limitless. But we’re picking some very particular battles to fight.” Conquering alien hordes on a Hollywood film lot for his latest project is one thing, but revolutionising the food industry armed with the tiny hemp seed is a challenge of a whole different order.

Snapshot

Name: Glynis Murray, Henry Braham

Place of birth: GM: Leatherhead, Surrey. HB: London

Family: Married with four children

Potted cv: GM: BBC drama department, then worked with Ridley Scott before launching own production company Tomboy Films. HB: Film, commercials, fashion, food

Best career decision: GM: Starting our own company and launching a food business. HB: Good Hemp brand

Worst career decision: Both: Haven’t made it yet

Career highlight: GM: Making Waking Ned and Nanny McPhee. And Good Oil being listed in Waitrose. HB: Haven’t got there yet

Best piece of advice: GM: Be brave but sensible. HB: Whatever you think, think the opposite

Business idol: Paul Arden (former creative director of Saatchi & Saatchi)

How do they relax: Watch rubbish films

Favourite film: GM: The Lives of Others and Gladiator. HB: Chungking Express

Favourite meal: GM: Sunday lunch. HB: Beans on toast