When maverick Austrian writer Peter Turrini wrote his debut 1967 play, Shooting Rats, he stipulated that anyone wanting to stage it must create a version relocated to the time and place of the production. Fanshen Theatre Company have transformed the cavernous Octagon Hall of Kennington's old Lilian Baylis School for Turrini's coming-of-age tale. Director Rachel Briscoe explains how she came upon the perfect rubbish dump.

In October last year we found ourselves in love with this play an Australian play called Shooting Rats about a first date the girl wants to be wined and dined but the boy takes her to a rubbish dump. We were sure that this was the right play to be the next project for Fanshen; now we just had to find the right space.

Directing in spaces like Theatre 503 and Arcola Studio 2 is great because it teaches you just how much you can do on a small stage. But since seeing Cheek by Jowl's production of The Changeling in the back area of the Barbican where a character picked up a chair and threw it at full force across the space, I've always wanted to direct in big spaces, spaces where actors can run at top speed, play intimate moments ten metres apart, throw things at each other.

Having this brilliant play, which needed a space bigger than any artistic director is going to let me loose on at this stage of my career, was the impetus I needed. I had this sense that there must be buildings in London that were empty and that you could transform. I asked various people who I thought would be knowledgeable about how to find spaces and was surprised by the answer I received from a friend who works as a location manager for films: "Oh, I just walk around until I find somewhere." It was both encouraging and scary to find out that there was no secret formula, no society of high priests of empty spaces and there was now no excuse not to start looking.

So we started. We'd look at a map, choose an area of London and walk around. We'd write down empty buildings and Google them when we got back to the office. It made us notice things about London that we'd never been aware of; the architectural peculiarities, surprises and the fact that when you look at it objectively, we live in an amazing city.

Compiling our short list through these mini walking tours, we started contacting the owners of these properties. Some didn't get back to us, some spaces weren't big enough, some were great but miles off the beaten track in deepest darkest Hackney. In good moments, I felt like the protagonist of a detective story; in bad moments I felt like an idiot. When London has so many theatres already, why was I trying to make another one?

In March I got an email back from someone I'd contacted about a large, high profile space, saying, basically, you must be joking, but saying they had another space which would be suitable and would I like to come and see it? I went, not getting my hopes up. It was a school hall and I had visions of my own school hall, with climbing bars on the walls and badminton courts marked on the floor.

Walking into the Lilian Baylis Old School Site Assembly Hall was a big surprise. A massive, cavernous room, with an octagonal pit in the middle, this was like no school hall I had ever sent. Built in the Brutalist architectural style like the Barbicanit felt harsh, unrelenting and unfriendly. Perfect for a rubbish dump.

Shooting Rats is at the Octagon Hall of the Old Lilian Baylis School, Kennington, from 6-24 October 2009.