Lawrence.com

London — "The Mousetrap" has turned 50, which prompts the question not whodunnit but whydidit?

How did this particular Agatha Christie thriller carve out so unusual a slice of show biz history?

After all, there are many stage mysteries, such as "Sleuth," that got better reviews. And quite a few London plays attract greater audiences these days.

But Christie's suspense drama long ago became a theatrical law unto itself, reliant not on stars or even full houses to turn a handsome profit.

"The Mousetrap" was to celebrate its 50th anniversary last Monday and its 20,807th performance with Queen Elizabeth II in the audience.

"The secret of its success is its longevity, and the two build on each other," said Stephen Waley-Cohen, who took over the reins from the original producer, Peter Saunders, in 1994.

Waley-Cohen wouldn't give exact figures but confirmed industry reports that the break-even point for the thriller, with its cast of eight, was around 30 percent in the 540-seat St. Martins Theater. "The Mousetrap" has been there since March 1974, after a 21-year run at the Ambassadors Theater next door.

The low break-even is highly enviable in an industry where many productions need to attract double that percentage of playgoers on a weekly basis to make financial sense.

That explains why "The Mousetrap" can ride out fluctuations in attendance that can cripple other shows. Another plus for producers: "The Mousetrap" has made its title the star, freeing producers from having to cast big, expensive names to keep it going. By contrast, the West End play "Art," which has run about six years, has had 27 casts :quot; many of them with stars :quot; in an effort to maintain interest in the comedy.

The original cast of "The Mousetrap" did have stars when the play first opened Nov. 25, 1952, during an era of post-World War II food rationing and identity cards. The original Detective-Sergeant Trotter was Richard Attenborough, who went on to become the Academy Award-winning director of "Gandhi," "Cry Freedom" and other films, as well as an actor in movies like "Jurassic Park."

But there have been no stars since then.

A star or two, Waley-Cohen added, "would skew the play, which is very much an ensemble piece."

The management tries to keep the production fresh, though. A completely new set was built 2 1/2 years ago, the first scenic overhaul in 35 years. And the show is recast every 10 months, with some 2,000 applicants each time, Waley-Cohen said. About 500 actors have appeared in "The Mousetrap" through the years.

Among the current cast members is 28-year-old Matthew Wilson, a graduate of London's Royal Academy of Dramatic Art. Wilson is the latest unknown to inherit Attenborough's role as Trotter.

How did Wilson regard getting a role that brings with it little attention or reviews and can look a bit declasse on a theatrical resume?

He recounted the story of a fellow actor, not in the show, "who made a bit of a joke about 'The Mousetrap' and 20 minutes later was asking me, 'How much do they pay you to be in that?"'

Like any sensible actor, Wilson acknowledged that work is work, even when the queen isn't in the audience.

"If nothing else," he said, "I'm walking on stage doing what I love to do and being paid for it at the end of the day."