Banks do it, brokerage firms do it, even AOL and Time Warner do it. So why shouldn't theater people join the mega-merger boom?

That's the reasoning that prompted a syndicate that includes composer Andrew Lloyd Webber to buy 10 theaters this week in the West End, London's equivalent of Broadway. With London's theaters running up records at the box office, Lloyd Webber said, he decided to buy the properties now to "be quite certain that we have got the theater in secure, theater-loving hands."

Lloyd Webber, who inflicted "Memory" and "Don't Cry for Me Argentina" on the world's elevators, explained at a press conference here that he sought the 10 theaters to make sure that London's stages are "not in the hands of pen-pushers and number-crunchers." The 10 were put on the market last year by the Australian investors the Stoll Moss group.

In fact, Lloyd Webber himself has been one of the most successful number-crunchers in the theater trade for 20 years or so, bringing a degree of stagnation to both the West End and Broadway in the eyes of his critics. He created a series of noisy, crowd-pleasing spectacles--"Cats" and "Phantom of the Opera" are the best examples--several of which have run for years in prime theaters. "Cats" has been playing in London and New York since the early '80s.

Accordingly, his syndicate's acquisition of 10 more theaters--to be joined in a new holding company with three he already holds--is "raising concerns about the diversity of West End theater," according to the Independent newspaper's theater correspondent Severin Carrell.

Still, theater lovers here generally applauded the news of Lloyd Webber's coup on the theory that it's better to have producers and composers running theaters than owners whose prime motive is the bottom line.

"Yes, there is concern about the sort of dumbing-down of the West End," said the Daily Telegraph's theater critic, Charles Spencer. "But Lloyd Webber--he's a genuine theater nut. He's keen as mustard to have quality plays on the stage. So I think this is almost 100 percent good news."

Stoll Moss has been marketing the 10 West End theaters as a group. There was considerable concern last year when it was reported that the leading bidder was an American theater combine, SFX Group, which already owns some London stages. "Some people did not want these gems to fall into American hands," Spencer explained.

But last weekend, Stoll Moss agreed to sell to a syndicate owned half by Lloyd Webber and half by a venture capital arm of London's National Westminster Bank. The buyers offered $144 million, a hefty price since most of the theaters will require considerable expenditures for repair.

But the syndicate--calling itself Really Useful Theatres, or RUT--is buying into the West End at a golden time. London's theater district last year broke all revenue records, with ticket sales topping $400 million for the first time. Theater is one of this city's strongest tourist attractions; people travel from all over the world for London weekends stuffed with two matinees and two evening shows.

A huge and growing part of that market, here as in New York, belongs to the blockbusters--the glitzy musicals that play on and on, primarily because travel agents in Oslo, Omaha and Osaka promote them to tourists.

The mega-hit "Buddy," for example--a fifth-rate play at best that happens to end with a feel-good reprise of Buddy Holly golden oldies--has sold out almost nightly for 11 years. Long-running musicals such as "Les Miserables" and "Blood Brothers" also depend on out-of-towners for most of their audience.

There is some fear that these old chestnuts could block the arrival of new productions that are quieter or quirkier. Last year's charming revival of the George and Ira Gershwin White House musical "Of Thee I Sing," for example, was shunted off to the tiny Bridewell Theatre in the financial district, where it died despite favorable reviews.

On the other hand, good plays still pop up regularly in the theater district. Michael Frayn's "Copenhagen"--a ferociously intelligent drama about nuclear physics--started off in a repertory theater in 1998 but made it to the West End last year and has been a hit. The play will open on Broadway this spring.

In any case, the momentum driving theater mergers seems to be as strong as the forces that spawn a new "biggest merger of all time" almost every month on Wall Street. In fact, Lloyd Webber has already announced that his RUT group is looking to buy some theaters in the United States.

CAPTION: Andrew Lloyd Webber's investment is raising concerns about the "dumbing-down" of the London stage.