As the government prepares to publish the results of its much-derided "national debate" on GM foods, the next controversial emerging technology - nanotechnology - is beginning to appear on supermarket shelves - and the trouble is we're about to make the same mistakes all over again.

Regulating GM has proved difficult largely because we didn't legislate fast enough. The crux of what we have done wrong with GM is to wait until GM products were already commercially established before stepping in. This has allowed the US, which hasn't shared Britain's concerns over either the environmental or the consumer protection impact of GM, to create and satisfy an international market for GM - and argue that European attempts to regulate GM are de facto discriminatory against US producers and driven by protectionism. Moreover, any environmental or social implications of the commercial production, import or consumption of GM foods will have potentially become reality before the regulatory regime designed to prevent them comes into effect. The horse will have bolted before the stable doors are slammed shut.

But these lessons have not been learned. Worse, the mistakes are set to be repeated over the emerging technology of nanotechnology, the catch all term encompassing the manipulation of particles at the nano-scale - one billionth of a metre - to enhance or change a material's properties and commercial value.

This shift in scale - which has only begun to be exploited commercially for the last five years or so - is perhaps best understood as the next "big down", from manipulating genes (GM) to manipulating molecular structure itself.

The current commercial value of nanotech stems from the fact that the properties of even well known materials change at the nano-scale, thanks to the effects of quantum mechanics. Titanium Oxide, for example, is an active ingredient used in sunscreens for its ability to reflect the sun's light and harmful UV rays. At the nano-scale, it stops reflecting light and therefore becomes transparent - and thus more commercially useful - while still maintaining its ability to reflect the harmful UV rays.

And while the technology might be small - smaller than ever before - the business is big. Current global spending on nanotech (public and private) is in excess of US$4 billion and rising. Over 30 national governments have now launched nanoscience initiatives, with Europe, USA and Japan competing for the lead. By 2015 global nanotech-related sales are predicted to exceed $1 trillion per year (US National Science Foundation) with all sectors of the economy being affected - from electronics and computing, defence and weaponry to energy, agriculture, pharmaceuticals, fabrics and cosmetics.

The proponents of nanotech claim it will deliver a brave new world free from poverty, hunger and drudgery. The truth would be laughable if it wasn't so tragic: current nanotech projects include transparent sunscreen, self-cleaning glass, ever-more destructive weaponry and stain-resistant clothes. In reality - like GM - nanotech is about providing a highly profitable "techno fix" for the problems of the affluent rather then addressing the root causes of inequality, poverty, hunger or disease.

What they are not telling us are the potentially grave risks nanotech poses to the environment, human health, consumer choice - not to mention social justice, equality and development.

Like GM before it, the ability to atomically modify matter - both living and non-living - will alter our societies, our economies and even our sense of ourselves. The nanotech revolution, however, is currently evolving quietly beneath the radar screens of government regulators and the public alike. No regulatory body has taken the lead to ensure that nanotech applications are safe and many of the hard questions have not yet been asked: Who will control nanotechnology? Who will determine the research agenda and who will benefit from nano-scale technologies? What mischief can synthetic nanoparticles create floating around in our ecosystem, our food supply and in our bodies? What happens when human-made nanoparticles are small enough to slip past our immune systems and enter living cells?

There is no conclusive data on the toxicity of nanotech products - even those already commercially available - and this is in flagrant disregard of the precautionary principle. What little research that has been done - by University of Liverpool toxicologist Dr Vyvyan Howard, for example - suggests the toxicity of nano-scale particles of any substance is significantly greater than a "macro" scale amount of the same substance. This should come as no surprise: while the regulations regard a nano-particle and a "macro" particle of the same chemical as "substantially equivalent" - with the same toxicity and impact - it is precisely because their properties differ in commercially useful ways that makes them interesting to business in the first place.

In truth no one really knows what the long-term effects of manipulating matter at the atomic level will be. We must therefore adopt an immediate moratorium on the commercial production of and research into nanotech - and especially the marketing of those products coming into direct contact with human skin or the food chain - until we can establish a regulatory framework based on the precautionary principle. As an absolute minimum this must include regulations on liability for the negative impacts of nanotech, strict labelling requirements and compulsory impact assessments.

Unlike the government, industry has learned from GM. Already it is presenting nanotech as a "scientific" issue rather than a societal one - often, incongruously, in the same breath as they proclaim its potential to herald a new industrial revolution.

The challenge for policy makers is to make sure they don't fall for this double-speak, and to ask the right questions about nanotech's social and environmental impacts. The most immediate priority must be to prevent those with most to gain from the new technology - big business - from winning a regulatory race before government has even arrived at the starting line. Otherwise we risk another shambolic "national debate" in a year or two's time that will have little, if any, potential for informing a regulatory regime. Another cat will have been let out of the bag that will be impossible to put back, whatever the implications of its escape.

Dr Caroline Lucas is the GreenMEP for South-East England