FOR Tadesse Meskela, there is no such thing as a typical day. On Tuesday he could be in New York. By Thursday he could be bound for Berlin. The next Saturday, he could be speaking in London or heading back home to Addis Ababa. Wherever he goes, however, coffee is the common factor, the overriding, obsessive concern. He drinks six cups a day and spends long hours discussing the inequity of the industry's trade system.

As the leader of Oromia Coffee Farmers Co-operative Union in Ethiopia, Meskela travels the globe on behalf of 100,000 growers, in search of those willing to pay a better price for the raw beans that produce some of the world's finest blends. If ever he misses his family, the desire for change acts as a powerful stimulant to carry on. "I have to work for my people, to help bring my people out of poverty," he explains. "It is important to get people to buy fair trade, to bring co-operative principals to the consumer world. My wife understands. She is pleased at the work I am doing."

Meskela's quest is the subject of a forceful new documentary film, Black Gold, made by brothers Nick and Marc Francis. Released in the UK next month, it shows with haunting clarity the discrepancy between the paltry amounts farmers receive and the gargantuan profits made in the West. It is already having an impact. Given a limited release in the US last year, Black Gold has roused sufficient outrage to frighten some of the biggest coffee corporations into justifying their buying practices.

Starbucks is particularly jittery, calling the film "incomplete" and sending representatives to screenings to counter any negative publicity. Ahead of a showing at the London Film Festival, the company emailed British employees to tell them the good work Starbucks is doing in investing for their farmers' future. The fight over Ethiopia's 1000-year-old coffee culture is now being played out on YouTube, as Dub Hay, head of Starbucks coffee team, posts clips about the company's commitment to social responsibility in response to a series of online trailers on the Black Gold website.

The Francis brothers are first-time independent film-makers unaccustomed to such high-stakes confrontation. "We have been surprised by how aggressive Starbucks have been," frowns Nick Francis, when we meet in their tiny London office. "Since we showed the film at the Sundance festival, they've gone on a PR campaign to discredit the film. That's the tell-tale signs of a company that's very, very worried. It creates more questions than it otherwise would and it has completely backfired on them. The film doesn't go out to discredit one company, but they're acting like it does."

Nick had travelled to Ethiopia years before making the film and was shocked to see the decline on his return in 2003 as he and his brother sought a suitable story to highlight trade injustice. "It was alarming to see how much the farmers were struggling, despite more and more coffee houses opening around the world. The basic system is unchanged. Coffee-producing countries are supplying the raw product to the market, but most of the money is being made after the beans have been sold."

The southern Ethiopia captured in Black Gold is a beautiful, surprisingly verdant place, with lush kaffa trees blossoming in tropical abundance. The oldest coffee growing region in the world, it produces the second most traded commodity on the planet for an industry worth $80 billion a year. Yet the film-makers found growers struggling to cope with the vagaries of a fluctuating market since the coffee price collapsed in 2001. Oxfam has estimated that an Ethiopian grower gets about three cents from a $3 cup of coffee sold in the West.

Some once-productive families have been forced to leave their farms and travel to emergency feeding centres, displaying their children's distended bellies and fragile bones in order to receive food and medical attention. With resources stretched, the "moderately malnourished" are turned away. "There may no longer be a colonial grip on Ethiopia," says Nick, "but we saw for ourselves that there is a trading system keeping people enslaved."

The brothers were deeply impressed by Meskela's co-operative and its efforts to take back some of the coffee's value from the chainofbuyers,suppliers,exporters, importers, roasters and retailers. "Tadesse was someone we came across who was trying to influence people for a better deal and bypass the way major international companies like to do things," says Marc.

By selling directly to Western companies, some of whom are willing to pay slightly higher fair trade prices for speciality coffees, the Oromia union ensures a small sum goes to improvement projects such as health centres and schools. Yet Meskela, a former farmer himself, insists this is not good enough. The minimum fair trade price of $1.26 per pound still takes its cue from the New York StockExchangeandhe believes this means it remains far too low. "We need the price to come to a $4 minimum to allow farmers to make a decent living. The cost of living is increasing daily here and there is a lot of expense to live as a human being, to buy corn and wheat, to afford health care, clothes, to send children to school. Fair trade prices are not a long lasting solution."

A visit to many coffee houses, where pictures of happy farmers adorn rustic woodenpanelsandantiquekettlessit neatlyondisplay,suggestssomething striking is happening in the branding of relationships with the third world. As one window display puts it: "Coffee tastes better when you know it's doing good."

Only 6% of Starbucks coffee is fair trade certified. As a speciality coffee chain, it does pay above average prices for gourmet blends. Those producing household varieties are not so fussy. Nestlé continues to buy over 99% of its coffee at market price and Kraft, owners of Maxwell House and Kenco, offer only one "sustainable development" brand, a non-fairtradecertifiedproduct.Despite declining to be interviewed for the film, these major players seem ever-more keen to proselytise such tiny gestures.

"Consumers need to be increasingly cautious and savvy when terms like fair trade' and social responsibility' have become so mainstream," warns Nick Francis."Companieslike Nestlé and Kraft have appropriated and hijacked that language, not because they have changed direction but because of the good PR it generates. At the three-second moment of purchasing choice, it can be very powerful branding."

Powerful enough to have a potentially devastating impact if the image is tarnished. Powerful enough for Starbucks chairman Howard Schultz to warn employees in a memo leaked a few months ago that the company was in danger of losing its "soul" and "the romance and theatre that was in play". Starbucks certainly attractedunfavourable notices during a recent copyright dispute when it vocally opposed the Ethiopian government's attempt to trademark speciality blends such as Sidamo and Harar to establish greater control over licensing deals. The company made an embarrassingclimbdown after meeting Addis Ababa officials in February. Their YouTube frontman Dub Hay was forced to apologise for calling the trademark bid illegal, though the company has yet to join the network of firms who recognise the trademarks.

Black Gold is causing more drama. The Starbucks Workers Union has now taken up the Ethiopian farmers' cause. Starbucks, meanwhile, has accused the film-makers of failing to offer solutions. The Francis brothers insist they offer an ambitious visionofgenuinely equitabletrading rules, the removal of restrictive tariffs and an empowered, business-minded Africa capable of producing and marketing its own coffee. "An Opec-style agreement for the coffee-producing countries would give them more power," says Marc, while Nick adds: "Until Ethiopia can compete with the multinationals with its own companies, there is still going to be this onus on the consumer to buy fair trade and ask for just a few more pence for farmers."

Meskela welcomes the amount that some of their buyers invest (Starbucks has spent $4.1 million in aid initiatives in coffee growing countries in the past two years), but remains adamant about economic self-determination. "Aid is not a solution for us. Why should we need aid? The assistance with the clean water projects and so on can be supportive of course, but we want to sell our product at a good price and make trade work for us. That is what is important."

It is a clarion call that is beginning to be heard at the highest levels. Earlier this year, the Co-operative Party arranged a screening of Black Gold for MPs at Westminster and set up a one-to-one meeting for Meskela with Tony Blair. "It was great for me," says Meskela. "I think Blair took the idea of making changes seriously. I hope so."

The Francis brothers are more sceptical about the outgoing prime minister. "He puts himself across as a champion of Africa but hasn't convinced," says Nick.

The Francis brothers have put other documentary projects on hold for as long as Black Gold continues to cause a stir. "We didn't expect to shake up the industry like this," says Nick. "When your central character meets Tony Blair, when you are getting phone calls from multinational companies, it can be overwhelming. But that's what film should be about: making something happen in the real world."

Black Gold is released on June 8 www.blackgoldmovie.com