At any other time, it is fair to assume, nobody would have noticed. How many of us have even heard of cumarin? However, the publication of the EU decision just days after the devastating tsunami changed all that.

When the news hit some of the Sunday newspapers in Britain it caused, if not exactly an outpouring of public fury, then at least a backlash against Europe, with more than a few British readers deciding that they would vote against the new European Constitution if they were ever given the chance.

The Business reported that aid agencies and charities were furious at the EU's hypocrisy in offering aid to developing countries while raising trade barriers to protect inefficient European manufacturers. It said the tariff had been denounced as criminal. It also called on European trade commissioner Peter Mandelson, a former British member of parliament and adviser to the prime minister, to promote free trade instead of imposing barriers.

The EU certainly deserved the blast. The insensitivity of the decision was breathtaking. It turns out the cumarin trade centres on the devastated Thai resort of Phuket, which took a terrible trashing from the tsunami. At a time when Thailand was asking the world for help and trying to limit the damage to its economy, it certainly did not need to face economic sanctions from Europe.

But it is also fair to argue that whoever had the bright idea of tipping off the newspapers about the new tariff had taken a cynical decision to exploit the tsunami for a political agenda. The EU looked bad and the Thai traders were portrayed as victims.

There are lots of points to be scored in the battle against EU protectionism by portraying Europe's executive commission as a nest of mean-spirited and heartless bureaucrats. For as long as the public's attention and sympathies are focused on the aftermath of the disaster, it would be folly to waste the opportunity to raise awareness of just how damaging western protectionism can be to fragile developing economies.

But anti-dumping duties and other protectionist measures deserve to be examined coolly, and the campaign against them broadened to look beyond trade in an obscure product.

Public attention will soon move elsewhere and the massive aid pouring into the region will have the usual mixed results, benefiting some, but also crushing others by distorting the local economy. Yet when the fuss has died down, the trade barriers imposed by Europe and the United States will remain and the damage will continue.

The EU sees the cumarin trade as a form of sanctions-busting, rather than a legitimate export. It portrays the traders as smugglers. Yet the only reason there is smuggling is because the EU has imposed an anti-dumping duty on direct exports from China, thereby forcing underground and criminalising what would otherwise be a perfectly legitimate and wholesome trade.

The same could happen to any other product. Thailand is the world's largest exporter of prawns. The EU reportedly told the Thai government to buy six European-made Airbus aircraft - instead of US-built Boeings - or face a 12 per cent duty on its prawns. Such tactics may be unfair, but they are effective.

However, a 12 per cent duty on prawns would probably have fostered new smuggling operations. Neighbouring Malaysia pays only a 4 per cent tariff. How long will it be before Thai prawns enter Europe through Malaysia, masquerading as Malaysian produce to avoid a punitive tariff?

The truth is that tariffs of any sort - especially anti-dumping duties - distort trade. They can do this by encouraging smuggling or, if equally applied to all exporters, by depriving exporting nations of their markets.

Poor countries often face higher tariffs than developed nations as the latter have greater negotiating power. Yet it is the developing nations which have the most urgent need to sell.

Europe and North America have a duty to allow Asia and Africa to grow and one of the best ways to do this is to ensure that developing countries find a ready market for their exports, which keep their citizens in work and allow them to earn enough to feed themselves.

When the immediate effects of the tsunami have been dealt with and the time has come to rebuild economies, it is not only the amount of aid that will determine how quickly affected nations recover, but also the openness of European and US markets to imports from the developing world.