Germany's Transport Minister, Mr Reinhard Klimmt, was sounding tough yesterday as he rejected calls for a cut in the "ecology tax" imposed on fuel by the governing coalition of Social Democrats and Greens. Pointing out that petrol is still cheaper in Germany than in other European countries, he said France and Britain would be happy to have German price levels.

"I don't want to talk about cutting taxes at the moment. We must hold our nerve. There is no reason to meddle with the ecology tax," he said.

But as German truck-owners threaten to follow the example of their French and British counterparts by blocking fuel supplies in protest against rising prices, the government's nerve may not hold for long. Ministers reportedly are considering a cut in car tax to compensate for the increase in petrol prices - a move that will outrage the environmentalist Greens.

Governments throughout Europe have watched with growing unease as the protests over the cost of petrol have spread from France to Spain and Britain. Most of the blockades so far have been led by the self-employed - truck-owners, fishermen and taxi-drivers - rather than workers. But as Europe's economy becomes more integrated, trade unions are increasingly looking for European solutions for problems that transcend national boundaries.

"Every day we see more and more the need to develop a common trade union approach. This is reality. Problems can't be solved in a national context any more. We are so interdependent, not only economically but also socially," according to Wim Bergans of the Brussels-based European Trade Union Confederation.

Although this week's protesters have been targeting their national governments, Mr Bergans believes that the problems created by the rise in oil prices can only be tackled at a European level. And he maintains that the oil price already has had a particular impact on everyone who lives within the euro zone.

"I'm convinced that the energy prices played a major role in the last increase of interest rates by the European Central Bank (ECB). We have an inflation rate of 1.5 per cent if you exclude energy prices and food prices. If you include them, we have 2.4 per cent. So this explains the quarter of a per cent increase in interest rates. It influences the whole of European life, that's clear," he said.

High oil prices and the continuing weakness of the euro could persuade the ECB to increase interest rates again this autumn, despite signs that economic growth in Germany and France is stalling. The ECB president, Wim Duisenberg, who was in Dublin this week, dismisses fears that increasing interest rates to keep down inflation could fuel unemployment. But with the jobless rate in the euro zone above 9 per cent, many of Europe's politicians and union leaders remain fearful of the effects of higher rates.

Mr Bergans argues that the launch of the euro and the influence of institutions such as the ECB on the economic life of Europe have made it more important that European workers should enjoy the same rights.

"Surely now that we have an internal market and we have the euro, the time has come to show Mr and Mrs Everybody that their social rights, their trade union rights, their cultural rights are recognised Europe-wide," he said.

At present, it is not legally possible to organise a Europewide strike but trade union leaders insist that European co-operation is now so advanced that they could co-ordinate national protests in such a way that they would affect the entire EU. Mr Bergans is not dreaming of pan-European strikes, however; he is more concerned with negotiating minimum standards for workers that will apply throughout the EU.

When EU leaders meet in Nice later this year, more than 80,000 trade unionists from all over Europe will be there to demand more protection for workers. But Mr Bergans admits that Europe's unions still have a long way to go before bargaining at a European level becomes the norm rather than the exception.

"Everybody realises that for a lot of aspects, trade union action within a country has reached its limits. We are all so interdependent on each other and this is absolutely recognised. But recognising something and always finding the right way to put it into practice are two separate things. This is something you can't do overnight," he said.