The United Kingdom and the European Union are complaining at the US move to penalise a range of imports from Europe in an increasingly bitter transatlantic trade dispute over bananas.

But tensions are also sharp on other economic and political issues.

There is:

• growing resentment of American exports of genetically-modified foods
  
• anger in Italy at the acquittal of an American military pilot whose plane sent 20 people in a cable car to their deaths last year
  
• and disagreement over policy on Iran, Iraq and Kosovo.

In the United Kingom, it is very rare for an American ambassador to be summoned by the government to receive a protest.

The only recent occasions were when the Sinn Fein leader, Gerry Adams, was granted an American visa in 1994, and when the United States mounted an invasion of Grenada in 1983.

So for the government to call in the American ambassador in London for the second day in a row is unprecedented.

And when a British minister describes the American measures in the banana war as irrational and unacceptable it is a sign of how acrimonious things have got.

Euro edge

The sharpest transatlantic disputes are economic, reflecting the interests that are bound sometimes to pit two of the world's three largest trading powers against each other.

The arrival of the European single currency, the Euro, gives a new edge to the rivalry.

In the banana war, there are grievances on both sides.

The Americans say the European Union has broken world trade rules by favouring banana imports from their former colonies in the Caribbean and Africa.

The Europeans complain that the United States is acting unilaterally without waiting for a ruling by the World Trade Organisation.

Other disputes concern American exports of hormone-treated beef and GM foods. The debate over food safety is more acute in Europe, especially in Britain, because of fears about mad cow disease.

Utopia, greed and lobbying

To quote one British newspaper article, the debate on genetic engineering in the United States has been effectively stifled by "the combination of wild-eyed techno-utopianism, stock market-fuelled greed and incessant lobbying by the genetic-industrial complex".

These arguments reflect in part different social and political values.

The American emphasis on free trade contrasts with the continuing European attachment to greater regulation.

But it is also the case that the Europeans are becoming more assertive politically, exploiting their economic weight on the world stage.

After the collapse of communism, they are less dependent on the US and more inclined to voice resentment of what they see as highhandedness by the only remaining superpower.

The execution in Arizona of a German citizen convicted of murder went ahead despite public appeals for delay by the German Government and the International Court of Justice, amid allegations of irregularities in American criminal procedure.

The United States insists on the supremacy of its own court system; last year it refused to sign up to the treaty establishing an International Criminal Court, finding itself opposed by the whole of Europe, but in the same camp as states like Iraq and China.

Italian rage

Now, there has been an outburst of rage in Italy at the acquittal by an American court martial of an American military pilot whose aircraft cut a cable car line a year ago and sent 20 passengers to their death.

The verdict came during a visit to the United States by the Italian Prime Minister, Massimo D'Alema, who found himself simultaneously having to deal with another transatlantic dispute - on policy towards Iran.

A group of American legislators wrote to Mr D'Alema asking him to think again about Italy's close relations with Tehran. The State Department has criticised a $1bn deal concluded with Iran by French and Italian oil companies.

Here politics and economics intersect.

Washington believes no concessions should be made to what it describes as rogue states which back terrorism and try to develop weapons of mass destruction.

The West Europeans take a less black-and-white view, often arguing that engaging with such governments is more likely to change their behaviour.

For many Americans, this is just a hypocritical cover for pursuing economic self-interest.

Kosovo tensions

The issue where the United States and Europe are most obviously working together is Kosovo. Yet even here there are tensions.

Some European officials complain that the Americans are too keen on Nato bombing to force President Milosevic into line, and have no follow-up policy if it does not work.

They point to Iraq, where last December's American and UK air strikes put an end to the UN weapons inspection regime, however defective.

All these arguments point to a global power structure which is dynamically changing.

The European Union is not yet capable - it may never be - of acting politically and above all militarily on a par with the United States.

Washington complains that the Europeans dither, that in Richard Holbrooke's words there is no one in Europe to call to get a decision.

From the Europeans' point of view, the United States demands that they take on more of the responsibility and cost of international action - but when they do assert themselves, Washington feels that its pre-eminence is being threatened.