Job: group chief executive, WPP
Age: 63
Industry: advertising, marketing
Turnover: £6.19bn
Staff: 110,000 (including associates)
Salary: £3.57m (including £1.65m bonus)
Worth: £106m
2007 ranking: 43

Sir Martin Sorrell built one of the world's largest advertising companies from scratch.

WPP employs 110,000 people in more than 100 countries, and is home to ad agencies JWT and Ogilvy & Mather, buyers Mediacom and Tempus, and PR firms Finsbury and Hill & Knowlton.

He is regularly described as the world's most influential ad man, and when he talks, people listen.

Sir Martin Sorrell. Photograph: Martin Argles His efforts to expand his vast company still further with the acquisition of market research business Taylor Nelson Sofres have been frustrated. But don't expect Sorrell to give up without a fight.

Sorrell has made three approaches to TNS, but was rebuffed on each occasion. TNS would prefer a merger with Sorrell's German rival GfK, much to the WPP chief executive's chagrin.

"He is the only proper global media player the UK has," said one member of our panel. "He is of international importance. With one of the biggest advertising companies in the world, Sir Martin Sorrell has huge clout."

It is now 23 years since Sorrell left Saatchi & Saatchi to buy wire basket maker Wire & Plastic Products. It has since been transformed into a marketing services empire.

Sorrell's opinions have huge weight, even more so in a time of economic gloom.

"I am still not sure there will be a recession in the US and I definitely don't think worldwide," said Sorrell, who expected 2008 to be buoyed by the triple effect of the US presidential election, Euro 2008 and the Olympics.

"At some point in time the rubber has to hit the road with increased oil prices and commodity prices, and our thesis - it might be wrong - is this is more likely to happen in 2009 than 2008," Sorrell told the Guardian. He has said he expects things to pick up again in 2010.

WPP reported profit before tax up 5.5% to £719m last year, on the back of turnover of £6.19bn.

Now 63, is it time for the WPP chief executive to hand over to the social networking generation? "As long as the old farts at the top of the company don't prevent change it's fine," he said.

The old fart is certainly well rewarded, and he is estimated to be worth £106m. Is he worth it? "I am not saying that - that's for others to judge. If I am not, they will say cheerio." Don't expect him to say goodbye for a little while yet.

Sorrell began his career working for Mark McCormack, the founder of talent agency IMG. He joined Saatchi & Saatchi in 1977 and was knighted in 1999.