Bryony Lavery is one of Britain’s busiest playwrights and her latest play, Beautiful Burnout, proved a big hitter for the Pleasance Courtyard at this year's Edinburgh Festival Fringe.

The much-anticipated collaboration between Scott Graham and Steven Hoggett of Frantic Assembly and the National Theatre of Scotland is a highly physical piece set in a Glasgow boxing gym where five teenagers dream of stardom (and seeing stars) in the professional ring.

Ahead of its London transfer to the genuine East End boxing venue of York Hall Leisure Centre in Bethnal Green, Lavery talks about what makes the show such a knock-out.

Had you always wanted to write a play about boxing?
I'd never thought about it, no. But I did have a lurking interest in boxing, that thing where I knew one should think it was brutal but never did. Then Scott and Steven took me out for lunch and said they wanted to do this, to take boxing to this exciting place where it becomes this beautiful, storytelling act. Of course, I'd do a story about a carpet with them. But I thought: this is a very good idea. And my interest has grown and grown since then.

How did you go about researching the show?
We visited Greenock Boxing Club and Terry's, both traditional Glasgow boxing gyms. We also went to see some amateur fights and one professional one. I remember stepping into a gym for the first time and seeing this small room crammed with young boys boxing each other. My immediate thought was: this is the safest place boys of that age could be. If they weren't here, they would be scrapping on the bus or getting bullied. And this wasn't about that. They're absolutely silent because they're so tired out and they do exactly what they're told.

So boxing can be a good thing, then?
Amateur boxing is just brilliant. I honestly don't know where I stand on the professional side. It’s a wonderful world but of course it has its dangers. Only two characters get to go professional in the play. One of them succeeds and one doesn't. But that's the moral dilemma - even with all the rules and precautions, you can become responsible for permanently injuring someone. I was very struck by referees we met who were haunted by matches they had overseen. That’s why I included the character of (referee) Steve George.

You also have a female boxer, Dina. Was that important to you?
Completely. I watched a lot of boxing films and felt strongly that I'm not having the girl who's just the girlfriend. Dina is amazing, as is Vicki (Manderson) who plays her. She can do every single routine the boys can do, in some cases better, and she doesn't want to be limited to 'women's boxing'. Perhaps that's not sensible but she feels it from her heart. She's as good as them. She should have the same chances as the boys.

How did you feel when you saw the play performed?
I thought I'd died and gone to heaven. It was when they moved into the space at The Pleasance and first took me through the door. The cast were just running through the end of the play, the sightlines were perfect and suddenly there was this boxing venue in front of me with all the red lights and screens. The idea of what it's going to be like in York Hall, a real East End boxing venue, is even more exciting.

The choreography is mesmerising. How much of the movement featured in your original script?
Honestly, what you're seeing on stage is about draft 527. It's the third time I've worked with Frantic so I knew how closely text and movement work together in their shows. And because we wanted to make it so physical, we took out text wherever possible. It's been really elastic and plastic the whole way through. It’s felt very creative.

Underworld's music is central to the show. Were you already familiar with them?
No, but Scott and Steve made me a tape! They would keep trying different tracks and I'd get these notes saying: "We're going to use ‘Scribble’" or "We're going to use ‘Kittens’". I just trusted them to find the right music. Take the final fight. I'd written pages of dialogue to describe what happened. But fading to 'Beautiful Burnout' at the moment his brain explodes says it all.

As a writer, is it hard to sacrifice your words to other elements such as movement, music or film?
The playwright's role is always to provide that moment when everything makes sense and it's heartbreaking to acknowledge that it rarely comes from the text. But once you take that truth on board, you're always writing for that point of absolute silence. When everyone in the room knows what they are feeling and thinking and seeing. In this play, it's absolutely right when it comes. There are no words for what has happened. Words themselves have disintegrated.

Were you nervous about critical and audience reaction to the play?
We're still all incredibly anxious. It's been about constantly moulding and moving things around. But we knew if we got it right, it could be something really special. I'm thrilled it's got such great reviews. Scott and Steve have taken boxing and moved it into the realm of art.

Beautiful Burnout runs at York Hall Leisure Centre from 16 September to 2 October 2010. Tickets are available from the Barbican website.