Anti-globalisation campaigner and author Noreena Hertz is using her MBA to fight inequality

It's a shame, says Noreena Hertz, that some people only use the MBA to jump up another rung on the corporate ladder. The precious knowledge and skills should be used for better purposes than being able to sell a few more boxes of cornflakes, she says. "I have this fantastic education and I want to use my time to make this a better world."

Hertz did not always see her life in that light. A precocious prodigy from a comfortable middle-class north London family, she went from the high-powered private school North London Collegiate to University College London, where she graduated aged only 18 in philosophy and economics. When she applied to Wharton Business School to study for an MBA, her GMAT scores were so exceptional that they decided to overlook her complete lack of business experience.

Her inexperience bothered her at first. She had never before met anyone who worked for an investment bank. And when, on the first day, her lecturer referred to "zero coupon bonds", she realised that the only word in the phrase she understood was zero. But she learnt fast, and majored in finance, acquiring a Wharton MBA aged only 21.

At first she wanted to be a film producer, and went to work for a big Los Angeles agency, Triad. In Hollywood you start at the bottom, however well qualified you are, and she worked in the mail room, which she says was full of MBAs from Wharton and Harvard and lawyers from Yale. But she had not been there long when one of her Wharton professors asked her to work with him in Russia. And soon she found herself, still only 23, just after the collapse of communism, working as a consultant for the International Finance Corporation, the World Bank's sister organisation, advising the Russian government on economic reforms.

And that's what changed her life. Perhaps she was never really going to be another sharp-toothed profits-focused young go-getter, latte in one hand and mobile phone in the other, covering moral qualms with shedloads of management jargon. But what she saw in Russia made it certain.

Her team's mission was to turn Russia into a market economy. But she says: "The country's traditions, culture and history could not just be razed overnight - the 'one size fits all' solution that we were trying to impose was not going to fit." She started asking awkward questions. What would happen when their recommendation to privatise everything caused the layoff of thousands of people? What would happen to the schools and hospitals - for under communism, the local factory provided local facilities?

Hertz was shocked by the answers she got. This was not about economics, or the wellbeing of the people, she was told. The point of privatisation was to take state assets out of state hands so that the Communist Party could never return. The people need not be looked after - the market would make sure they were all right. Noreena Hertz was sure it would not - and looking at Russia today, who can doubt that she was right? The gainers have been privatisation barons like Boris Berezhovsky and Roman Abramovitch. The losers are people like one of Hertz's Russian friends, an English professor who cannot afford a basic basket of groceries.

Hertz saw that privatising everything would, as she put it, "incur a huge social cost". That discovery, she says, has dictated the course of her life ever since. She came back to Britain and studied for a Cambridge PhD in economics and business, went to work at Cambridge's Judge Institute of Management and set to work on her first book, The Silent Takeover: Global Capitalism and the Death of Democracy. It caused exactly the stir she hoped for, and she made a film for Channel 4 film called The End of Politics.

The Silent Takeover was lavishly praised and savagely attacked in equal measure, and launched her as a new sort of thinker - the first prominent British radical left winger to come out of the business schools. Now 34, she has a research post at Judge and shows no sign of losing her radical edge. Whenever she teaches MBA students there, she tries to give them a sense of their responsibility towards the communities, towns and nations in which their companies will work.

"We have to get our priorities right," she says. "$900bn (£500bn) was spent last year on global security, and only $50bn (£27.7bn) on aid. If we put more into aid, we would not have to spend so much on security. It's not a question of available resources but what we choose to do with them. We can choose to live in a safer and fairer world, or we can choose not to."

Her latest book, just published, IOU: The Debt Threat and Why We Must Defuse It (Fourth Estate, £16.99) is about the human consequences of what governments and companies have done to the Third World since the Second World War. "Children in Africa," she writes, "die every single day because their governments are spending more on debt servicing than they do on health or education." The money was lent by western banks and governments to corrupt regimes whose leaders were certain to steal much of it for schemes that were never going to benefit the people. The banks did it for short-term profit. The Governments did it for short-term advantage in the Cold War, and as soon as the Cold War was over, they demanded repayments.

Hertz's MBA taught her "the language and mindset of business leaders", but increasingly her work is aimed not just at the business community but at a general audience. Her writing has the directness and the common touch which academics and business people often find suspect, but she makes no apology for this. "I write books and make television programmes for a general audience, because politicians will change when they know that it is in their interest to change."