IT’S not often a genuine Master of the Universe jets into town, but then again Donald B Marron, one-time giant of Wall Street, just might be over here a little bit more in future.

“There are certainly areas we are looking at in Europe,” he says, sipping his trademark Earl Grey tea with lemon.

Marron is the former boss of Paine Webber, the securities bank he sold to UBS for $12.8 billion (£7 billion) in 2000, reportedly pocketing $100m in the process. He now runs his own private-equity firm, Lightyear Capital, a $750m fund which has its eyes on opportunities over here.

Lightyear has already bought the Parisian brokerage Julius Baer, relaunched as Kepler last month, and is sniffing round for more. Financial services, “yellow books”, radio stations, cable — he’s interested.

“What we aim to do is find interesting companies and make intelligent investments,” he says. “In most cases we make control investments, in other words, we exercise control but we expect good management to run the companies.”

He smiles gently. An impossibly tall — 6 ft 6 ins — skeletally thin and impeccably courteous man, New York-born Marron has been a sizable presence in American finance for more than two decades. He built up and sold four different firms, culminating in his 20-year stint heading Paine Webber as it grew to become one of the most successful operations on Wall Street.

Almost as a sideline, he also assembled what is probably the largest collection of contemporary art in corporate hands, now known as the UBS Paine Webber Collection, worth hundreds of millions of dollars. And he’s still buying. When Donald Marron flies in, the art dealers drop everything. “Yeah,” he drawls, “I’ve had an invitation to dinner tonight from Jay Jopling. Do you know him?”

Best take your chequebook. He gives a deep gravelly laugh. Even at 69, looking slightly stooped and with a face well weathered by wrinkles, Marron is razor-sharp, especially when it comes to money.

Sitting in a sixth-floor meeting room at Claridges hotel — his usual port of call when in London — with two female aides, and his second wife and family downstairs, Marron says that this time his visit is mainly holiday. That, you presume, means art buying, and a bit of sightseeing. Next time, it may be to do some major corporate shopping.

The purchase of Baer, says Marron, was simply a stepping stone. “It’s a business we understood, just research and sales. And I also felt it would provide significant additional access to Europe for us. We are a US firm and we look wherever the opportunities are.”

Such as? “Well, there are some financial-service businesses which start in the US then come to Europe. We’ve bought a very fine student-loan business in America, one of the biggest direct-to-consumer businesses, and we’ll be looking at that over here.”

Likewise Lightyear’s investment in an American home- equity business. “That’s a business that has real potential here,” he says. “And we’re also looking at areas like media, let’s call it more basic media: cable, radio stations, yellow books. And consumer-product companies. So we’re looking for opportunities, and hopefully this article may, you know . . .”

Yeah, I know. Marron’s eyes give a little flash of recognition. Beneath the old-fashioned, East Coast courtesy — “Am I sitting okay for you, sir?” he says to the photographer — there is a far tougher streak that has made him a controversial figure for some. Too rich, too powerful, part of a breed of American money men who did well for their clients, and maybe even better for themselves, and then bought themselves political influence in Republican circles, he arouses strong feelings.