WHAT a time to be a car boss. The soaring cost of oil, political pressure to reduce CO2 emissions, consumer panic over petrol and diesel prices. Then imagine you are running two car companies.

“These are not problems,” says Carlos Ghosn, perched on the edge of his seat, “these are challenges. Every car manufacturer is going to have to deal with this. How do we modify the technology? How do we modify the product? How do we modify the message to the market in order to make a return?”

Ghosn, chief executive of Renault and Nissan, barely draws breath. It’s been that way for three years, since he added the top slot at the French firm to his Japanese posting. Back then, most in the business world were astonished that one man thought he could run two global companies based 6,000 miles apart, even if they were in semi-merged “alliance”.

Now the whole car industry faces very different problems. Imagine if you were launching a new 4x4 next month?

Oh, that’s Ghosn, too. Renault’s Koleos is on sale in Britain from July 4, part of an extraordinary run of models that the French firm is pushing through. Ghosn loves new products, and he always wants them quicker — but who wants a 4x4 now? Sales in Britain fell 18% last month.

“For people who need a 4x4 it’s still a must,” retorts Ghosn. “You just have to make sure it is the most fuel-efficient and has the lowest CO2 emissions.”

Short and impish, Ghosn, 54, has an answer for everything. He speaks English fast with Brazilian intonation, hands going this way and that, his feline eyes darting round the room.

He’s a natural performer, and one of business’s global superstars. Born in Brazil to Lebanese parents, trained in Paris as a mathematician and engineer, he first won acclaim for his revival of Nissan — sent in by Renault — then trumped that by running the French firm, too.

Only General Motors, Toyota and Ford outstrip Renault and Nissan combined, but Ghosn won’t merge his firms — tied by cross-shareholdings since 1999 yet run separately — and that must take a toll. He spends a fortnight in Paris, then a fortnight in Tokyo, with travel elsewhere in between.

How does he cope? By being “super-organised” and having “no room for amateurs” round him. And because it’s important.

“We said from the beginning that if our companies don’t keep clear, distinct identities, then you spend a lot of energy fighting a resistance. And you can say we’ve been wise, because everyone else who tried mergers and alliances, they disappear.”

Ruthless, immodest and charismatic, Ghosn has only one gear: fast forward. Last week he was meeting Gordon Brown — Nissan’s plant in Sunderland is one of Britain’s great manufacturing successes. Next week it could be India, China or America.