Les Miserables is set to become the world's longest-running musical. It will overtake Cats, another Cameron Mackintosh production, on 8 October by which time it will have been seen by a total of 58 million people in 38 countries and in 21 languages.

It's a far cry from 1985 when the production opened at the Barbican to damning reviews that cast doubt on whether it would even transfer to the West End.

The French Revolutionary saga, written by Alain Boublil and Claude-Michel Schonberg and based on the classic Victor Hugo novel, transferred to the Palace Theatre in December 1985 before moving to its current home at the

Queen's Theatre in 2004. Over the years, it has starred Michael Ball, Ricky Martin and Ruthie Henshall among others. To mark the record, there will be a specially devised finale at the evening performance on 7 October.

Sir Cameron said: "I'm thrilled we've managed to reach this milestone. If someone had bet me when we opened that Les Miserables would last five years, I would have taken them on and been glad to have lost the bet. I never thought its subject matter could have made it anything like the hit it has become."

He added that the show's historic theme combined with its score was responsible for its enduring appeal, saying: "There is no reason why Les Miserables cannot go on for at least five years or more."