There were times in history when the issues confronting the World Summit on Sustainable Development, which has just ended in Johannesburg, might have seemed soluble. In late Victorian times, say, when the British civil service ruled a worldwide empire and British municipalities had brought clean water and sanitation to the teeming cities of the industrial revolution. Or in the late 1940s, when the democracies had organised to defeat Hitler and then reconstructed a ruined Europe, when Roosevelt's New Deal was still fresh in the memory and Aneurin Bevan's NHS the latest wonder of the world. At such moments, people had every reason to believe in the effectiveness of concerted state action. Today, that faith is lost. Paradoxically, just as human ingenuity seems ready to cross previously unthinkable boundaries - changing the nature of our own and other species, for example - saving the planet or ensuring minimum living standards for all its inhabitants seem beyond us.

The decline of confidence in government is profound. Not so long ago, a public agency could get men to the moon and governments could agree internationally on a successful plan to repair the ozone layer. Today, even in its traditional functions - internal security and external military action - government is widely expected to fail, as shown by the debate on war in Iraq, where the objections to US action are often based not so much on morality as on the likelihood of disaster.

What is supposed to be the development summit's greatest success - an agreement to halve the number of people without access to clean water and sanitation by 2015 - is a very good illustration. This is literally a matter of life and death: even as the summit was going on, 50,000 children will have died for the lack of these services. Yet where is the money and organisation to come from to realise such an ambition, which involves connecting 140,000 people to a safe water supply and 240,000 to adequate sanitation every day for the next 12 years? To be sure, there are private companies willing to invest, but only if they can expect a return in the form of water charges. Even today, the vast majority of people in developed nations - including 90 per cent of Americans - get their water from sources that are publicly owned and publicly operated. As the boss of Suez, a French company with international interests in water, has said: "Water is too essential to life to be a commodity." This may be just a politically correct way of saying that he sees no profits in supplying water to poor rural areas in developing nations, but it is hard to disagree. However, it is precisely because the Johannesburg pledge is bound to involve substantial state expenditure, and state activity, that the US was so reluctant to sign up. And even now it has been signed, the agreement involves no extra money and no plan for implementation.

This explains the gloom among many of those who attended the summit. They have no expectation that governments can enforce the agreed targets, feeble as many of them are. The private sector, on the other hand, is strong, confident and determined. In many people's judgement, the best hope of implementing the Kyoto targets on carbon emissions (themselves inadequate to stop global warming) is to convince business, and particularly US business, that there will be lucrative new markets in alternative energy sources. And, indeed, any sincere supporter of free markets would see the oil corporations and the oil-producing countries for what they are: a cartel, trying to corner the market in energy. But the planet is surely doomed if we always have to wait for propitious business conditions before we can save it.

Before the summit, many environmentalists criticised the extent of corporate involvement, arguing that business was hijacking the agenda. "The corporations are moving into the vacuum left by the heads of state, and asserting their claim to global governance," wrote George Monbiot. Yet John Prescott, writing in this issue (page 12), sees public-private partnerships (often including NGOs) on the global stage as a positive development just as he does at home. And he is right to argue that sustainable development has a better chance if the private sector signs up to it, rather than always regard it as an anti-business plot. But partnership is one thing, dominance another. The failure to end the subsidies, tariffs and quotas that keep poor countries' products out of western markets is just one example of how government in many countries now seems exclusively to serve corporate interests. The west is fond of preaching the virtues of disinterested, uncorrupted, democratic government to the peoples of the developing world. It sets, alas, a very poor example.

The price of bread

Edward Heath gravely warned, during the 1970 election campaign, that inflation had reached such levels under Labour that "you'll soon have the half-crown loaf". "The housewife", a being to whom politicians then addressed all statements about food, would not stand for it, Mr Heath said. A half-crown would be 12.5p in today's money; soon after the Tories' election, the price of the proverbial loaf passed three shillings, or 15p. Now, the £10 loaf approaches, with Waitrose charging £9.62 for the dense, chewy and very posh Poilane loaf. Perhaps this is another tribute to capitalism's amazing adaptability. The state struggles to convince the middle classes of the merits of progressive taxation. But a supermarket easily persuades the fashion-conscious residents of Belgravia to cough up 50 times as much as the poor folk of Bermondsey for what, if truth be told, is more or less the same thing.