LONDON — In 2001, following the lukewarm reception that greeted his musical version of “The Witches of Eastwick,” Cameron Mackintosh said he would never produce a new tuner again.

Times change.

A decade later he’s in previews with “Betty Blue Eyes,” a new £4 million ($6.4 million) musical based on Alan Bennett’s screenplay for the 1984 cult comedy movie “A Private Function.”

There are solid reasons Mackintosh, 64, has been wary of new work. For starters, he’s been remarkably busy with blockbuster “Les Miserables.” He and his office also are overseeing more than a dozen major productions, from Belgium to South Korea, of such titles as “Mary Poppins” — now in its fifth year on Broadway, on the road in the U.S. and about to open in Australia — “The Phantom of the Opera,” “Oliver!,” “Miss Saigon,” “My Fair Lady” and a U.K. tour of “Avenue Q.”

And that’s before anyone starts counting the licensed productions worldwide. And the seven West End theaters he owns and fills with a balance of tuners and plays, the latter often coming from the Donmar and the National.

If that weren’t enough, as announced in Variety, he’s preparing a world tour of a new version of “Phantom,” starting at a regional U.K. theater in March.

Mackintosh doesn’t simply invest in his productions. A notoriously hands-on producer, he’s been a highly active presence in pre-production and rehearsals of “Betty Blue Eyes,” discussing orchestrations and analyzing and fixing numbers with a creative team headed by helmer Richard Eyre, who also directed “Poppins.”

So what about that no new musicals quote?

“What I actually said is that I wasn’t looking for new musicals,” Mackintosh says. “I had come to the age when I realized that I doubted that I would be the one to find the great new breakthrough musical in the way that I was lucky enough to do with Andrew Lloyd Webber 20 years before.”

Not everything has been coming up roses for Mackintosh lately. He brought the entire U.S. company of “Hair” to Blighty — adding around $82,000 per week to the running costs — but audiences stayed away from the American flower-power musical.

“In the end, it didn’t mean as much as I would have hoped to the English theatergoing public,” he says.

“Betty Blue Eyes” would seem a similar gamble. There are no musical-theater names in the cast — its leads are TV actors with unproven tuner track records — and although Bennett has given the show his blessing, it’s no longer his script, and his name is not on the publicity.

“For me (“Betty Blue Eyes” is) an artistic rather than a financial gamble,” Mackintosh says. “The truth of the matter is that I’m well-heeled enough to be able to afford for it to fail.”

The score for the show by composer George Stiles and lyricist Anthony Drewe (who supplied the new material for “Poppins”), has a retro sound because, following the film, it’s set in 1947. In a happy confluence with contempo Brit concerns, it’s a time of austerity marked by the coldest winter in decades, rising unemployment and an impending royal wedding — that of then-Princess Elizabeth, today’s monarch.

Stiles and Drewe’s score incorporates everything from swing to English pastoral. They were already interested in the idea of musicalizing Bennett’s small-town comedy “Private Function” about a henpecked podiatrist, a social-climbing wife, the wedding party and an illegal runaway pig when they were contacted by Ron Cowen and Daniel Lipman. Best known as exec producers on “Queer as Folk,” they had bought the rights from Handmade Films and already written a script.

Around 18 months ago, after a discussion with Stiles and Drewe’s agent Patricia Macnaughton. Mackintosh talked over their ideas and asked to see a script for a forthcoming workshop of the show. Almost immediately he took it on, not least because he felt it was already in such good structural shape.

Eyre signed on a couple of months later, bringing onboard a team headed by choreographer Stephen Mear (“Mary Poppins”), designer Tim Hatley (“Monty Python’s Spamalot”) and lighting designer Neil Austin (“Red.”)

“I did it because I found it so original,” Mackintosh says. “It’s so unusual now to find a show that is completely propelled by words both in the lyrics and script.”

In an era dominated by jukebox musicals more assembled than written, he has a point. But he’s also at pains to emphasize the quality of the music.

The future of the show remains to be seen. “My instincts are that Toronto would be a very good place to go if, please God, we’re a great success,” he says. “Look, I’ll be thrilled if we settle into a lovely run here.”