You'd have thought things couldn't get any better for Sir Terry Leahy. After all his company takes one in every eight pounds spent by Britons. But the Tesco boss could net a £11.5m windfall if he manages to pull off the launch of the retailer's much anticipated Fresh & Easy convenience chain in the US.

Given the might of Tesco it would be easy to assume that Sir Terry would head any list of multiple retailers by default, but his ambition and relentless drive to do things exactly the way he wants are every bit as impressive as the size and sheer momentum of the Tesco juggernaut.

Take carbon labelling, for example. Tesco has been working with the Carbon Trust but has not adopted its esoteric labelling system, as he's not happy with the model.

Some might argue this is Tesco's way of trying to derail initiatives where it hasn't got full ownership but it also shows that Sir Terry, who has spent his entire career at the retailer, won't adopt anything unless it is absolutely perfect.

At the same time Tesco has led the way in green initiatives, such as its store in Wick, Scotland, which is Britain's greenest supermarket.

Yet it is the retailer's brave move across the Atlantic that has once again shown Tesco to be the most ambitious of the big four. Like Sir Terry himself, who grew up on a Liverpool council estate, Tesco's aspirations know little bounds.

As he has proved on countless occasions, rivals underestimate him at their peril. Sir Terry is known for his almost encyclopaedic knowledge of the retail market, not just in the UK but across the world, and this will prove a valuable weapon in trying to crack the US.

"Intellectually he is second best to very few chief executives," says Oriel Securities analyst Jonathan Pritchard. "He is peerless in his absolute dedication to make Tesco an extremely successful retailer."

Competition is mounting from his rivals but so far he is showing no signs of fatigue. The only thing Tesco has to worry about is who will eventually replace him. However, knowing Sir Terry, it won't be for a while yet.