As representatives from the two top trading powers, their relationship could make or break the talks to liberalise commerce.

United States trade representative Robert Zoellick and European Union trade commissioner Pascal Lamy are responsible for keeping the WTO trade negotiations on track to meet a January, 2005 deadline.

It's a tricky task. Having overcome the hurdle of the 1999 Battle of Seattle, when trade talks collapsed amid mass anti-globalisation demonstrations, a new round of negotiations was initiated in Doha in 2001, with the goal of bringing down trade barriers in key sectors such as agriculture, services and manufactured goods.

Since then, they have had to negotiate US-EU trade disputes, which still threaten to upset the Doha round. Next up is a testing ministerial meeting in Cancun in September.

The two men, both marathon runners and avowed workaholics, are proud to call themselves ascetics. They are aware of their potential to spoil the US-EU trade dynamic and appear eager to avoid the sort of personal acrimony that soured relations between their predecessors, Charlene Barshefsky and Leon Brittan, which helped make commercial disputes all the more bitter.

"Some of the things that we have to deal with could put quite a strain on our relationship. So it is just as well that I have a strong personal admiration and even affection for Bob, even if his personal best for the marathon is rather better than my own," Mr Lamy said recently in Washington, the lion's den for any European trade commissioner.

Although from different parts of the political spectrum - Mr Lamy is a Socialist and Mr Zoellick a Republican - their careers are similar. Mr Lamy is the classic French fonctionnaire and was the right hand man to former European Commission president Jacques Delors. He has also been a Group of Seven sherpa - a diplomat who prepares the meetings for G7 leaders - as was Mr Zoellick, who worked for former president George Bush. They both then went into business, before taking their posts as the world's top two trading representatives.

Mr Lamy became European trade commissioner in 1999 and Mr Zoellick the US trade representative in 2001. The two now manage a relationship which accounts for 40 per cent of world trade and which has led to Europe and the United States being called the elephants of global commerce.

These two pachiderms have said they are determined not to crush the Doha Round, despite trans-Atlantic trade disputes and the threat of billions of dollars of WTO sanctions in the US-EU steel brouhaha.

Peter Guilford, a former trade spokesman at the European Commission and now a consultant in Brussels, says that if any one could get the Doha talks finished on time, it was Mr Lamy and Mr Zoellick.

"The number and scope of EU-US trade disputes are diminishing," he says. "Trade barriers between Europe and America are very low, and both sides are now more focused on opening world markets together than squabbling between themselves."