It is time once again for that touching annual ritual, in which the world's most powerful people move themselves to tears. At Heiligendamm they will emote with the wretched of the earth. They will beat their breasts and say many worthy and necessary things - about climate change, Africa, poverty, trade - but one word will not leave their lips. Power. Amid the patrician goodwill, there will be no acknowledgement that the power they wield over other nations destroys everything they claim to stand for.

The leaders of the G8 nations present themselves as a force for unmitigated good. Sometimes they fail, but they seek only to make the world a kinder place. Bob Geldof and Bono give oxygen to this deception, speaking of the good works the leaders might perform, or of the good works they have failed to perform - but not mentioning the active harm. They refuse to acknowledge that what the rich nations give with one finger they take with both hands.

Look at what is happening, right now, in the Philippines. This country has many problems, but one stands out: just 16% of children between four and five months old are exclusively breastfed. This is one of the lowest documented rates on earth, and it has fallen by a third since 1998. As 70% of Filipinos have inadequate access to clean water, the result is a public health disaster. Every year, according to the World Health Organisation, some 16,000 Filipino children die as a result of "inappropriate feeding practices".

These are the deaths caused only by acute results of feeding children with substitutes for breastmilk. A summary of peer-reviewed studies compiled by the campaigning groups Infact and Ibfan suggests that breastfeeding also reduces the incidence of asthma, allergies, childhood cancers, diabetes, coeliac disease, Crohn's, colitis, poor cognitive development, obesity, cardiovascular disease, ear infections and poor dentition. Switching from bottle to breast could prevent 13% of all childhood deaths - a greater impact than any other measure. Panaceas are rare in medicine, but the mammary gland is one.

Both the government of the Philippines and the UN blame the manufacturers of baby formula for much of the decline in breastfeeding. These companies spend over $100m a year on advertising breastmilk substitutes in the Philippines, which equates to more than half the department of health's annual budget. Those who appear most susceptible to this advertising are the poor, who are also the most likely to be using contaminated water to make up the feed. Some spend as much as one third of their household income on formula. Powdered milk now accounts for more sales than any other consumer product in the Philippines. Almost all of it is produced by companies based in the rich nations.

Since Ferdinand Marcos was deposed in 1986, the government of the Philippines has been trying to stand between these corporations and vulnerable mothers. It has failed. It plugs one loophole; the formula companies find another. Baby Milk Action, one of the world's most impressive public health campaigns, has compiled a dossier of breaches of the marketing code drawn up by the World Health Organisation. Formula companies have been dispensing gifts to both health workers and mothers, running promotional classes and meetings and advertising their wares on television and in magazines and papers. These practices, though mostly legal in the Philippines, are all discouraged by the code.

In February this year, the Pharmaceutical and Healthcare Association of the Philippines (Phap), which represents multinational companies, ran a series of advertisements expressing concern for women unable to breastfeed their children. The campaign was described by Jean Ziegler, the UN's special rapporteur on the right to food, as "misleading, deceptive, and malicious in intent". He claimed the adverts "manipulate data emanating from UN specialised agencies such as WHO and Unicef ... with the sole purpose to protect the milk companies' huge profits, regardless of the best interest of Filipino mothers and children".

Last year, in the hope of arresting this public health disaster, the Philippines' department of health drew up a new set of rules. It prohibited all advertising and promotion of infant formula for children up to two years old. It forbade the formula companies from giving away gifts or samples, and from providing assistance to health workers or classes to mothers. The new rules seem stiff, but they all come straight from the WHO's code. Phap, whose members include most of the world's largest pharmaceutical companies, went to the supreme court to try to obtain a restraining order. When it failed the big guns arrived.

The US embassy and the US regional trade representative started lobbying the Philippines government. Then the chief executive of the US Chamber of Commerce in Washington - which represents 3m businesses - wrote a letter to the president of the Philippines, Gloria Arroyo. The new rules, he claimed, would have "unintended negative consequences for investors' confidence". The country's reputation "as a stable and viable destination for investment is at risk". Four days later, the supreme court reversed its decision and imposed the restraining order Phap had requested. It remains in force today. The government is currently unable to prevent companies from breaking the international code.

So the department of health asked a senior government lawyer, Nestor Ballocillo, to contest the order. In December Ballocillo and his son were shot dead while walking from their home. The case remains unsolved; Ballocillo was working on several contentious cases at the time. Last month the US regional trade representative paid another visit to the Philippines government. The department of health appears to be wavering. In two weeks the campaigners promoting breastfeeding will present their arguments to the supreme court to try to get the order lifted, and the formula companies will try to stop them. If the companies win, thousands of children will continue to die of preventable diseases.

The pressure to which the US government and the US Chamber of Commerce has subjected the government of the Philippines is at odds with almost everything the G8 now claims to stand for: the millennium health and education goals, the eradication of poverty, fair terms of trade. But the G8 nations will pursue their stated objectives only to the point at which they collide with their own interests. Away from their sentimental summits, they pull down everything they claim to be building.

The G8 demands action on climate change; the World Bank, controlled by the G8 nations, funds coal burning power stations and deforestation projects. The G8 requests better terms of trade for Africa; Europe and the United States use the world trade talks to make sure this doesn't happen. The G8 leaders call for the debt to be reduced; the IMF demands that poor nations remove barriers to the capital flows that leave them in hock. The G8 leaders simultaneously wring their hands and wash their hands: we have done what we can; if we have failed, it is only because of the corruption of third world elites.

The question is no longer whether the undemocratic power the G8 nations exert over the rest of the world can be used for good or ill. The question is whether it will cease to be used.

monbiot.com