It might be a real case of 鈥渙ops, there goes my trousers鈥 during the classic farce Noises Off.

The male cast have to drop their trousers on a regular basis as part of the plot, but they鈥檝e had to get costumes with tighter waists to stop it happening accidentally.

During three months of touring the play, which hurtles along at a breakneck speed, the weight has been dropping off them.

鈥淚 can commend the Noises Off diet,鈥 says Neil Pearson, who is bringing the play to Birmingham.

鈥淎ll the men in the cast are on their second, much smaller costume. We鈥檝e all dropped at least two inches from our waistline thanks to all the running about we do.鈥

Michael Frayn鈥檚 play, now 30 years old, is a farce-within-a-farce. Neil plays Lloyd Dallas, the exasperated director of Nothing On, in which young girls run about in their underwear, men lose their trousers and doors continually bang open and shut.

Act One of Nothing On is played out three times 鈥 first in rehearsal, next while viewed from backstage on the first night and then again viewed from the front during its final disastrous performance.

The middle act has been described as 鈥渢he most difficult single act to perform ever written鈥.

鈥淚t鈥檚 certainly the most difficult act to rehearse I鈥檝e ever come across 鈥 it鈥檚 virtually impossible,鈥 muses Neil, the 54-year-old star of TV dramas like Drop the Dead Donkey, The Booze Cruise and Between the Lines.

鈥淚t鈥檚 a really tricky 25 minutes. Usually you鈥檇 rehearse with others and then go away and work on it on your own, muttering the lines to yourself while walking the dog.

鈥淏ut you can鈥檛 rehearse that act unless you have the entire cast, director and set. Nobody speaks, and you can鈥檛 rehearse the tremendously complex moves on your own as you need other people.

鈥淒uring rehearsals, you usually get a growing sense that it鈥檚 beginning to work. But with Noises Off, it just doesn鈥檛 work and doesn鈥檛 work and doesn鈥檛 work, and then, if you鈥檙e lucky, it finally sparks into life. Then you have to keep it working.

鈥淚 think it鈥檚 the funniest play in the English language and that comes with its own pressures. You know that it has worked before, so if you can鈥檛 make it work, it鈥檚 your fault.

鈥淏ut now it鈥檚 up and running, it鈥檚 fabulous. Well, apart from the danger aspect. I鈥檝e worked on plays that scare me but not one that has been so physically dangerous.

鈥淚鈥檝e been OK, fortunately, because I don鈥檛 have to fall down two flights of stairs or run up them with my shoelaces tied together. But others in cast have suffered a dislocated shoulder and an injured hand and there have been plenty of visits to chiropractors.

鈥淚t works very well as a comedy, but it鈥檚 also a magic act. The audience marvels while it鈥檚 happening, then afterwards thinks 鈥榟ow did they do that?鈥.鈥

Neil saw the original West End production starring Patricia Routledge, Paul Eddington and Nicky Henson back in 1982.

鈥淚t was only a few performances old but already it was becoming a classic,鈥 he remembers.

鈥淚t鈥檚 written by a scientist, who also wrote Copenhagen and Democracy. Frayn has an extraordinary breadth of interest and talent. He鈥檚 brought his forensic mind to understanding what makes people laugh.

Neil Pearson with other cast members of Noises Off, at the New Alexandra Theatre, Birmingham.
Neil Pearson with other cast members of Noises Off, at the New Alexandra Theatre, Birmingham.

鈥淭he star of any farce isn鈥檛 the cast, it鈥檚 its mechanism and how intricately it is put together. And Noises Off is brilliantly put together.

鈥淢ind you, Frayn changed it a lot in 1982. Originally in the third act he tried to inject an editorial element to darken the mood and align it with the chaos which we were living through.

鈥淏ut by that point the audience were helpless with laughter and didn鈥檛 want to be reminded of reality. In the end, the cast, through Nicky Henson, told him when the show was finished because they refused to take any more rewrites.鈥

The current production of Noises Off began life at the Old Vic, breaking box office records. The cast includes Maureen Beattie, David Bark-Jones, Chris Larkin and Geoffrey Freshwater and is directed by Lindsay Posner.

鈥淲e get on rather better than the cast of Nothing On, because we have to,鈥 says Neil.

鈥淲e rely on each other for laughs and also to prevent accidents.鈥

It is Neil鈥檚 first appearance on stage at Birmingham鈥檚 New Alexandra Theatre, though he remembers appearing in the studio at Birmingham Rep in the early 1980s, in a production of Trafford Tanzi.

Next for Neil is an appearance at the International Beckett festival in Enniskillen, though he says: 鈥淚 will be taking most of August off. After Noises Off, I need to lie down in a darkened room for a while.鈥

* Noises Off plays Birmingham鈥檚 New Alexandra Theatre from June 24-29. For tickets ring 0844 871 3011 or go to .