LONDON -- If anyone can succeed with a show Harold Prince and Michael Bennett couldn't make pay, it's probably Cameron Mackintosh.

After wowing London's West End with such blockbuster productions as "Cats" and "Les Mise'rables," Mackintosh sent these musicals across to America, where they are currently bowling over Broadway. "The Phantom of the Opera," also playing to packed houses here, is due to continue Mackintosh's transatlantic winning streak when it opens in New York this fall.

Now Mackintosh is poised to take what is perhaps the inevitable next step -- turning around a loss-making American musical for the London stage, and then bringing it back to Broadway.

"Follies," written by Stephen Sondheim and James Goldman and staged by Prince and the late Bennett on Broadway in 1971, became a legend of the musical theater -- though it was a financial flop. On July 21, Mackintosh's all-new "Follies" opens here. Featuring British stars like Diana Rigg and Julia McKenzie, it's already done close to $1 million in advance ticket sales. And ultimately, Mackintosh says, he dreams of bringing it "back to Broadway."

With other London revivals of American shows also possibly heading across the Atlantic, "that really is the English stage sending coals to Newcastle," says Sheridan Morley, theater critic for the International Herald Tribune and Punch magazine.

"I don't believe in all this crap that's written about the British invasion," says Mackintosh, recently back from meeting the Japanese imperial family when "Les Mise'rables" opened in Tokyo. "It just happens that at this moment more musicals are coming out of Britain than anywhere else."

Mackintosh wants "Follies" to cross the Atlantic not to prove a point but "to bring it home," he said. "It belongs on Broadway."

Mackintosh has been daydreaming about doing "Follies" for more than 10 years, ever since he produced "Side by Side by Sondheim" in London. "Luckily with my run of successes I was in a position to actually make it happen," he said.

To many, including its creators, "Follies" marked a turning point in musical theater history, when productions broke free from the traditional, typically upbeat, Rodgers-and-Hammerstein-type framework and entered the age of the plotless or concept show -- the age of "Cats" -- when almost nothing seems outside musical bounds.

"Follies" was a show full of desolation, a tale of the reunion of a group of fictitious Ziegfeld-type showgirls, focusing on the lives of two unhappily married couples.

"All of us who were involved in the show when it was originally done were very proud of it," says Goldman, who wrote the book. "It came out very much as we hoped it would."

Produced and directed by Prince, choreographed and codirected by Bennett, with leading ladies like Alexis Smith and Dorothy Collins, "Follies" dazzled much of its audience. "A brilliant show, wonderfully entertaining, extraordinarily intelligent, and having both a stunning direct appeal and a rare complexity of feeling and structure," raved Jack Kroll in Newsweek.

Even those who didn't like it were impressed. Citing "deficiencies," Variety wrote: " 'Follies' is far from having a clear track ahead, and yet it compels awareness and respect."

"Follies" ran for more than a year -- not particularly long by Broadway standards, but not too short either. It's said that many of the people who came to see it came back again and again. But they weren't enough to fill the house. When "Follies" closed, according to a spokeswoman for Prince, its backing angels lost 90 cents on each dollar of the $700,000 they had put in.

But the faithful, albeit limited, "Follies" audience grew into a cult following that was to give the show a larger-than-life image -- and keep it alive. In September 1985, they packed New York's Avery Fisher Hall twice to hear the likes of Carol Burnett, Barbara Cook and Mandy Patinkin sing the score.

Mackintosh never saw the original "Follies," but when he approached Sondheim about reviving the show he knew he wanted something different. "I had no wish to put myself in the position of trying to be a latter-day Hal Prince or Michael Bennett," he said. "I don't want to compete with two great giants of the theater."

The people behind this "Follies" continually stress that it's a very different animal from the show that died in America 15 years ago. For one thing, Sondheim has written four new songs. And in his first theater venture since the original (he's been doing film, television and novel work in between), Goldman has written what may ultimately be called a new book.

Much of the criticism of the original "Follies" surrounded its libretto, which some found confusing and others said bordered on monotonous. Mackintosh stops short of those who said Goldman's talk didn't live up to Sondheim's songs, but he did believe some reworking was needed.

"Obviously the book wasn't complete or wasn't completely successful, but I don't think that's the only reason the show didn't work," Mackintosh said. Still, "I didn't think there was any point in my doing it unless it was rewritten ... Times have changed. I wanted the book ... to have a more realistic tone."

Though conceding the possibility of some lack of clarity in the original production, Goldman stands fast behind his original work. "We thought that show was carved in marble," he said.

"It was no one's intention to rewrite the show in order to attract a larger audience" this time around, he stresses. "I originally said to Cameron, 'Well, you know, probably 5 to 10 percent of this needs adjusting, and Cameron said, 'That sounds fine to me.' "

But "the more I looked at it, the more I didn't like it any more," Goldman said. "When I originally wrote it I was involved in a terrible marriage, and I was in the midst of a divorce when it went into production, and everything was awful." Now, happily married to his second wife Bobby, "I didn't feel that way anymore, and I didn't want my characters to feel that way. It isn't what I wanted the evening to say about growing older, about regret, about the passage of youth and the fading of beauty and times gone by."

Where one "Follies" couple used to be poor, now they're rich. Where their problems once seemed soluble only by divorce, their lives are now more complicated -- their conflicts are with themselves as much as each other. "My private hunch," Goldman says, "is that the vast majority of people who have fond memories of the show ... will feel that it's different somehow, but they won't know how."

It may still elude some of its audience. "This show is not a tired businessman's show and it never will be," the writer warned. "In a show of this kind I have to make demands of you ... We're not going to tell you things three times. Occasionally we'll tell you something twice. But usually we'll tell it to you once."

Mackintosh budgeted his "Follies" at about $2.6 million -- more than "Les Mise'rables" but less than "Phantom," and a little more than one-third of what he says it would have cost to stage it on Broadway today. As it is he'll be "shoehorning" to keep it within budget, he said: "It's probably the biggest show I've ever done in my life." He's brought in a lot of big talent: Mike Ockrent directing, fresh from success with "Me and My Girl"; Bob Avian, who worked with Bennett on the original "Follies," choreographing, and designing, Maria Bjornson, acclaimed for her "Phantom" sets.

"I know it's a risk," says Mackintosh. "Every one of us involved knows it's a risk. We've all done it because we've loved it," with participants across the board working for "far less than their reputations deserved ... In the end all you can do is your best."